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    Home » Recipes » Cakes

    Published: Aug 3, 2021 by Nicole This post may contain affiliate links.

    Pastel Rainbow Unicorn Cake

    Jump to Recipe Print Recipe

    This pastel-colored unicorn cake is 3 layers of tasty fun and magic. Made with an upgraded boxed cake mix recipe and a whipped cream cheese frosting, this cake is as tasty as it is pretty.

    a side angled view of a finished unicorn cake with pink, purple, and blue hair

    I was recently tasked with making my niece a birthday cake (okay, I volunteered to do it). But only because I was just dying to make an easy unicorn cake for somebody and she was the perfect unicorn-loving candidate.

    I took a box of cake mix and gave it a bit of an upgrade to make it flavorful, moist, and enough of a batter to fill (3) 8 inch cake pans. This would give us the perfect unicorn height and enough cake to share with everyone too.

    The filling of this colorful unicorn cake is a simple box of vanilla pudding, (the cook and serve variety). Made and chilled per box instructions. This is my super simple cheat filling for my birthday cake crepes recipe too! It tastes pretty close to homemade pastry cream but without all of the added work, so of course, it's a go-to favorite of mine. 😉

    When combined together, the cake, the filling, and the frosting all make for a perfect rainbow unicorn birthday cake that is light, fluffy, moist, and oh so delicious.

    Why This Recipe Works

    1. It's easy. While there are several time consuming steps, the actual manual work needed to make this cake is fairly simple. Perfect for an at home baker.
    2. It's a cheaper alternative. You can buy a cake from a store or professional, or you can make one at home. Making them means there are more memories and love in every slice while keeping a little more money in your wallet.
    3. You can customize it. Change up the colors or flavors as you want and really make this recipe your own!
    Jump to:
    • 🥘 Ingredients
    • 🍽 Equipment Needed
    • 🔪 Instructions
    • 🍴 Recipe Tips
    • 📖 Recipe
    ingredients needed to make the batter of the unicon cake

    🥘 Ingredients

    For the Cake, You will Need:

    Yellow Cake Mix- This will be the base of the cake recipe, making it easier and more simplified. You can use Yellow or white cake mix.

    All-Purpose Flour- For added gluten, giving us a better structure.

    Granulated Sugar- This will make the cake more tender and help the consistency as well.

    Salt- For a natural flavor enhancer.

    Instant Pudding Mix- You will need the dry mix from the pudding box. Do not prepare it beforehand.

    Large Eggs- Use eggs to bind the cake together well.

    Sour Cream- This adds a lot more moisture and richness.

    Vegetable Oil- For the necessary added fats, use vegetable oil or canola oil.

    Milk- You'll need some milk for added moisture.

    Vanilla Extract- This is a flavor enhancer.

    For the Filling, You Will Need:

    Pudding- You will need Vanilla Flavored Cook and Serve Pudding (plus the milk to make it).

    For the Frosting, You Will Need:

    Heavy Whipping Cream- This will make the frosting fluffy and light.

    Powdered Sugar- Use powdered sugar to make the frosting smooth and sweet.

    Cream Cheese- Adding cream cheese will give us a great flavor, but it also helps the frosting to remain stable enough to pipe decorations with.

    Vanilla Extract- A flavor enhancer.

    🍽 Equipment Needed

    BeeyondCereal is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.

    • Mixing Bowls
    • (3) 8 inch cake pans
    • Measuring Cups
    • Measuring Spoons
    • Food Coloring
    • Electric Mixer
    • Frosting Piping Tips
    • Unicorn ears and horn decorations (you can find online at Amazon or in the cake section of Walmart!)
    • Frosting bags
    • Large flat surface for smoothing the cake like these acrylic cake scrapers

    🔪 Instructions

    Check out how to make unicorn cake with these simple step-by-step instructions:

    Batter Prepping

    Preheat your oven to 350 degrees F.

    Cut some parchment paper circles the size of the bottom of your cake pans and then spray the sides and bottom of the cake pans with non-stick cooking spray before placing the parchment paper in and spraying them again. This will keep the parchment paper in place so that it doesn't curl up.

    Set the pans aside and prepare the batter.

    In a very large mixing bowl, combine the dry cake mix, flour, sugar, salt, and boxed pudding mix with a whisk.

    cake mix and dry ingrdients in a mixing bowl
    wet ingredients and eggs in a mixing bowl

    In another mixing bowl, blend together the eggs, sour cream, oil, milk, and vanilla.

    sour cream added to blended egg mixture in mixing bowl
    smooth and evenly mixed wet ingredients in a mixing bowl

    Add the wet ingredients into the dry ones and then whisk together until well blended and no flour streaks remain.

    dry ingredients and wet ingredients in the same mixing bowl
    cake batter in a large mixing bowl

    Baking and Leveling

    Divide the batter between small bowls and add food coloring to each. Stir until the desired colors have been achieved.

    cake batter divided into different sized bowls ith drops of food coloring in each
    food colored bowls of cake batter

    Spoon the batter into the cake pans, a little at a time from each color until all pans are filled evenly and no unused batter remains. Use a toothpick to swirl the colors around if desired.

    a cake pan with parchment lined bottom surrounded by bowls of colored cake battter
    cake batter being added to cake pan in dollops

    Bake in the oven at 350 degrees F for 25-30 minutes or until a toothpick can be inserted and come out clean.

    a filled cake pan of colorful splashes of pastel cake batter
    aerial view of one baked layer of rainbow pastel cake in pan on a wire rack

    While the cakes are in the oven prepare the vanilla cook and serve pudding according to package instructions and place plastic wrap over the surface of the cooked pudding as it cools to prevent thick skin from forming.

    Once the cakes have finished baking allow for them to cool in the pans for 10 minutes before flipping over onto a cooling rack.

    Allow to cool completely before using a bread knife to level the tops.

    cake in a cake pan on a wire rack with a serrated knife on top and a leveled cake top

    Prepare the frosting as directed by the recipe card below. Place 2 cups of frosting in a covered bowl in the fridge for later (this will be the unicorn hair).

    Place some frosting into a piping bag or Ziploc bag with the end snipped off and on two layers of cake make a full ring around the leveled top.

    Spoon your pudding filling into these circles. The frosting will help to keep the pudding from leaking out when stacked. Try not to overfill the cake layers.

    two rounds of cake with frosting rings and pudding filling on a wire rack
    three stacked layers of cake on a golden cake board

    Stacking and Decorating

    Stack the three cake layers so that the filling is between two layers and the empty layer is the one on top.

    If you feel your cake needs more stability you can trim a few (like 3) paper straws to just a little shorter than the height of the cake and place them around the center of the cake, going through the layers like dowels.

    You can also freeze the cake at this point if you're making it in advance or wanting it to be more solid when you apply the frosting layers (less crumby that way).

    When the cakes are stacked and sturdy, Pipe some white frosting around the centers and sides of the cake. Make sure to get the top as well.

    first coat of frosting added to stacked layers of cake

    Take a long flat surface like a cake lever and go around the sides of the round cake, holding the leveler at a slight angle towards the cake, about 45 degrees. This will push the frosting into the cake as it smooths it out so it can help to fill in gaps and holes. Go around until the cake is covered in a thin layer. It's perfectly fine for crumbs to be stuck in the frosting.

    final white frosting layer added to three stacked layers of cake

    Chill the cake and the frosting at this point before doing a final frosting layer. If your cake was frozen solid, you may be able to get away with adding a thicker frosting layer now that the crumb layer is chilled against the cold cake.

    Add a thick layer of frosting around the sides and top and level it out until smooth. I say thick but really you want it no more than ¼ inch thick as your only goal is to make the frosting thick enough that the cake isn't poking through the sides. The top doesn't matter and can be left as a crumb layer because you will be covering it in unicorn hair frosting.

    Place the cake back into the fridge as you prepare the hair colors.

    Unicorn Hair

    Remove the chilled frosting you set aside earlier and mix it with any unused white frosting you have leftover from frosting the cake.

    Divide the frosting by however many colors you want and add some food coloring to each, mixing until blended.

    Place each frosting into its own piping bag with a fitted tip. A different tip should be used per color as it helps to make things less confusing and more unique.

    Arrange the bags of frosting in order of largest tip to smallest tip as this will make it easier to grab and use.

    Grab the cake from the fridge and set it in front of you. Plan out how you want the hair arranged. Do you want the full top covered or just a strip down the middle? Do you want large bangs or small? Etc.

    Once you've got an idea, go for it! Grab the largest tip and make several circles starting in the front and working your way back. Set down the frosting bag and grab the next tip.

    Use it to fill in some of the gap areas by making circles that are smaller or make stars by pressing down on the tip and lifting straight up. Continue this process until you get to your last color and use that to fill in any of the small gaps still left.

    Add sprinkles to the hair if desired.

    Add the unicorn horn and ears; if you haven't already, add the unicorn eyelashes too. These usually come with unicorn kits but can also be made with melted chocolate too.

    a fully finished unicorn cake with horns, ears, and eyelashes on a golden cake board

    Slice, Serve, and Enjoy!

    ~Happy Birthday To You~

    a birthday party showing the unicorn cake bing presented to a table full of children
    Presenting the Unicorn Cake to the Birthday Girl and Guests

    🍴 Recipe Tips

    Bowl Size:

    When making this cake it's important that you have a very large mixing bowl. A standard-sized large mixing bowl is a very tight fit for all of these ingredients and a bowl bigger than that is ideal. In our family, this is usually the bowl reserved for Momma's Potato Salad.

    Food Coloring:

    You don't have to divide and color the batter if you don't want to, but I think it makes for a fun and unexpected surprise to tie in the pastel colors for this DIY rainbow unicorn cake. Even just dying each layer its own color is a cool idea. Using gel food coloring for the batter and frosting is ideal for getting vibrant colors without adding in too much moisture. Not only that but a little gel coloring goes a long way.

    Prepping:

    Make sure that the pudding filling is either cooked and cooling before you begin making the cake layers or shortly thereafter so that the cake is cooled around the same time. This is especially important if you plan to bake and stack on the same day but both the layers and the filling can be prepped a day in advance. Freeze the cake layers while the filling remains in an airtight container in the fridge.

    Leveling:

    Using a large bread knife to level the cakes is great but my favorite trick is to cut off the dome of the cake before removing the layer from the cake pan. This way, you can use the cake pan as a level-gauge so that the cake tops are all cut off to an even height. You can choose to remove the layers and use a Wilton cake leveler tool for thinner but flatter layers if desired.

    Smoothing:

    Smoothing out the frosting for the unicorn is a big part of getting the unicorn to look right. While using an actual frosting smoother is ideal, I have used (clean) wooden rulers in the past so don't overlook basic house items and office supplies when in a pinch.

    a slice of rainbow unicorn cake ready to eat

    More great cake recipes to try soon

    • Summer Raspberry Cake
    • Easy Chocolate Orange Cake
    • Easy Unicorn Pull-Apart Bread
    • Banana Pound Cake with Brown Sugar Glaze
    • Peanut Butter Cream Cheese Frosting
    • 21 Unicorn Food Ideas To Inspire Your Next Party!

    📖 Recipe

    an upclose side view of the rainbow unicorn cake
    Print Recipe
    5 from 1 vote

    Rainbow Unicorn Cake

    This pastel-colored unicorn cake is 3 layers of tasty fun and magic. Made with an upgraded boxed cake mix recipe and a whipped cream cheese frosting this cake is as tasty as it is pretty
    Prep Time 1 hr
    Cook Time 30 mins
    Total Time 1 hr 30 mins
    Servings: 16 slices
    Calories: 613kcal
    Cost Recipe $10.26 / Serving $0.64
    Prevent your screen from going dark

    Equipment

    • Mixing Bowls
    • (3) 8 inch cake pans
    • Measuring Cups
    • Measuring Spoons
    • Food Coloring
    • Electric Mixer
    • Frosting Piping Tips
    • Unicorn ears and horn decorations
    • Frosting bags
    • Large flat surface for smoothing the cake like these acrylic cake scrapers

    Ingredients

    Cake

    • 1 box Yellow Cake Mix (just the dry stuff!) ($1.00)
    • 1 cup All-Purpose Flour ($0.08)
    • 1 cup Granulated Sugar ($0.22)
    • ¾ teaspoon Salt ($0.08)
    • 1 small box (3.4oz) Vanilla Flavored Instant Pudding Mix ($0.98)
    • 4 large Eggs ($0.32)
    • 1 cup Sour Cream ($0.80)
    • ½ cup Oil ($0.24)
    • 1 cup Milk ($0.19)
    • 1 tablespoon Vanilla Extract ($0.04)

    Filling

    • 1 box Vanilla Cook and Serve Pudding (Prepared) ($1.36)

    Frosting

    • 2 ¾ cups Heavy Whipping Cream ($2.72)
    • 1 cup Powdered Sugar ($0.23)
    • 8 oz Cream Cheese, softened ($1.98)
    • 1 teaspoon Vanilla Extract ($0.02)
    • Food Coloring in Desired Colors
    US Customary - Metric

    Instructions

    • Preheat your oven to 350 degrees F.
    • Cut some parchment paper into circles that can fit at the bottom of your 8 inch cake pans. Spray cake pans with non-stick cooking spray and lay the parchment circles inside. Spray again with cooking spray and set aside.
    • In a large mixing bowl whisk together the cake mix, flour, sugar, salt, and boxed pudding mix.
    • In another mixing bowl blend together the eggs, sour cream, oil, water, and vanilla.
    • Add your wet ingredients to the dry ones and mix until well combined and no flour streaks remain.
    • Divide the batter between small bowls and add food coloring to each one. Mix until the color is evenly distributed.
    • Divide the batter evenly between your three cake pans by using the same scoop measure (I use a small cookie scoop) and adding a mixture of each color into each pan. Each cake pan should look blotchy like it's a tie-dye of fun rainbow colors. Use a toothpick to lightly swirl the colors together if desired.
    • Bake in the oven at 350 degrees F for 25-30 minutes or until a toothpick can be inserted into the center and come out clean.
    • While the cakes are in the oven, prepare the vanilla cook and serve pudding according to package instructions and cover the hot pudding with plastic wrap to prevent a skin from forming. Remove it from heat and allow it to cool until ready to use or place it in the fridge.
    • Once the cakes have finished baking allow them to cool in the cake pans for about 10 minutes before flipping over onto a cooling rack to finish cooling completely.
    • Allow them to cool on the racks upside down and make sure to remove any parchment paper from the bottom of the cake.
    • Once the cakes are completely cooled, flip them over onto a cutting board and level the tops with a large bread knife.

    Prepare the frosting

    • In a large mixing bowl cream together the cream cheese and powdered sugar until just combined. Do not overmix.
    • In another large mixing bowl beat the heavy cream and vanilla until stiff peaks form.
    • Add the cream cheese mixture to the whipped cream and beat again until combined. Do not overmix.
    • Remove 2 cups of frosting and set aside (covered) in the fridge. This will be divided and colored later for the unicorn mane.

    Assembly

    • Place two topless cake layers in front of you and leave the other off to the side.
    • Place some frosting into a pastry bag or Ziploc baggie with a corner snipped off.
    • Make a circle around the rim of the tops of them both.
    • Spoon in your cold and chilled vanilla pudding. Spread it around so that it fills the circle and is pretty even looking.
    • Stack the three cakes on top of each other by placing one pudding topped cake on top of the other and the one you had set aside on top of the other two. Try to get them to stand as straight as you can. If needed, place everything into the fridge to chill for one hour so it holds up better. You can also freeze the cake at this point and chill the frosting until ready to use.
    • When the cakes are stacked and sturdy, pipe the white frosting around the outside where the middles are and go around the cake with a flat leveler or surface (a wooden ruler works okay in a pinch). Angle it slightly so you're pressing into the cake while removing excess frosting. This should fill in any gaps so the cake is level on the sides.
    • Frost the entire cake with a nice thick layer of white frosting so that it is about ¼ inch thick and you can't see the cake poking through. Go over it again with your flat leveler as much as needed to get it to look as desired. Don't forget to level out the top.
    • Place the cake in the fridge to chill as you prepare the colored frostings.
    • Remove your chilled frosting and add it to any leftover white frosting you may have (assuming it's not filled with cake crumbs).
    • Divide the frosting by however many colors you want in the hair and then add food coloring to each bowl and mix until well blended.
    • Place each frosting in it's own pastry bag with fitted tip. A different tip per color really helps to make things less confusing. You want to use the tips advertised as borders or stars as these look nicer than the round ones or leaves (unless you want to add leaves on purpose).
    • Arrange each bag once filled and fitted to the side in the order of biggest tip to smallest. This makes it easier to grab and use.
    • Bring your white frosted cake out of the fridge and set it in front of you. Plan how you want the hair to go. Do you want to cover the whole top or just a strip cascading down the side at an angle? Most unicorn cakes have bangs.
    • Once you have an idea in mind, grab your largest tip and pipe large circles in the direction you want them to go. Try to keep them spaced out so other shapes can fill the gaps.
    • Grab the next color and add smaller swirls or stars around the large ones in the gaps you provided, leaving space for the next colors too.
    • Repeat until there is only one small frosting tip left and use it to carefully fill in any white spots in the hair.
    • Add any sprinkles (if using) and place in the ears and horn. If you haven't already, add the eyes. These often come in kits with the horn and ears but if not, you can mix a little frosting with black food coloring or use melted chocolate.
    • Slice, serve, and enjoy!

    Notes

    Recipe Tips

    Bowl Size: When making this cake it's important that you have a very large mixing bowl. A standard-sized large mixing bowl is a very tight fit for all of these ingredients and a bowl bigger than that is ideal. In our family, this is usually the bowl reserved for Momma's Potato Salad.
    Food Coloring: You don't have to divide and color the batter if you don't want to, but I think it makes for a fun and unexpected surprise to tie in the pastel colors for this DIY rainbow unicorn cake. Even just dying each layer its own color is a cool idea. Using gel food coloring for the batter and frosting is ideal for getting vibrant colors without adding in too much moisture. Not only that but a little gel coloring goes a long way.
    Prepping: Make sure that the pudding filling is either cooked and cooling before you begun making the cake layers or shortly thereafter so that the cake is cooled around the same time. This is especially important if you plan to bake and stack on the same day but both the layers and the filling can be prepped a day in advance. Freeze the cake layers while the filling remains in an airtight container in the fridge.
    Leveling: Using a large bread knife to level the cakes is great but my favorite trick is to cut off the dome of the cake before removing the layer from the cake pan. This way you can use the cake pan as a level-gauge so that the cake tops are all cut off to an even height. You can choose to remove the layers and use a Wilton cake leveler tool for thinner but flatter layers if desired.
    Smoothing: Smoothing out the frosting for the unicorn is a big part of getting the unicorn to look right. While using an actual frosting smoother is ideal, I have used (clean) wooden rulers in the past so don't overlook basic house items and office supplies when in a pinch.

    Nutritional Information

    Serving: 1slice | Calories: 613kcal | Carbohydrates: 71.5g | Protein: 6.9g | Fat: 34.2g | Saturated Fat: 17g | Polyunsaturated Fat: 2.1g | Monounsaturated Fat: 11.5g | Trans Fat: 0.7g | Cholesterol: 119.1mg | Sodium: 528.8mg | Potassium: 183.7mg | Fiber: 1.7g | Sugar: 49g | Vitamin A: 282.5IU | Vitamin C: 7.4mg | Calcium: 140.7mg | Iron: 0.9mg
    Author NicoleDurham
    Course Dessert
    Cuisine American
    Tried this recipe?Mention @BeeyondCereal on Instagram and hashtag it #BeeyondCereal
    To view how this recipe was calculated you can visit my Pricing Disclosure Page for more information.

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    I'm Nicole and I am the owner and recipe developer here at Beeyond Cereal. I love saving money and one of the best places to trim expenses is in the kitchen. With this site, we are serving up tasty and frugal homemade dishes that the whole family will enjoy.

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