Rainbow Heart Cake

sliced hidden rainbow heart chocolate bundt cake on a wooden cake stand and a plate below it.

5 from 1 vote

A super awesome rainbow heart hidden inside of a chocolate bundt cake, what could be more fun? This Rainbow Heart Cake is made using boxed cake mixes, which just cuts down on the effort, without sacrificing the WOW factor.

Prep Time30

Cook Time35

Waiting Times30

Total Time1 35

Course: Dessert

Cuisine: American

Diet: Vegetarian

Servings: slices

Calories: 265kcal

Author: Nicole Durham

Cost: Recipe $6.92 / Serving $0.58

Equipment

Ingredients

Rainbow Heart Cake

1 box (15.25 ounces) yellow cake mix, prepared according to package directions ($1.80)
Rainbow food coloring, as needed

Chocolate Cake

1 box (15.25 ounces) devil’s food cake mix, prepared according to package directions ($1.80)
1 tablespoon cocoa powder ($0.09)

Chocolate Ganache

1 ⅓ cup semi-sweet chocolate chips ($1.74)
1 cup heavy whipping cream ($1.49)

US Customary - Metric

Instructions

Preheat & Prep: Preheat the oven to 350°F. Line a baking sheet with parchment paper.
Prepare Yellow Cake: Prepare the yellow cake batter according to package directions.
Color the Batter: Divide the batter evenly into 6 bowls or piping bags. Add food coloring to each portion and mix until the desired colors are achieved. Transfer to piping bags if needed and snip the corners.
Pipe & Bake Hearts: Pipe thin stripes of colored batter onto the prepared baking sheet, keeping the stripes narrow so they fit within a heart shape. Bake for 10 to 15 minutes until set. Allow to cool for 10 minutes.
Cut & Freeze Hearts: Cut heart shapes from the baked cake, placing them close together to maximize use. Discard scraps. Freeze the hearts for 10 to 30 minutes to firm.
Prepare Chocolate Batter: Prepare the devil’s food cake batter according to package directions.
Prep the Pan: Grease a bundt pan thoroughly and dust with cocoa powder to prevent sticking.
Add Base Batter: Pour about 1 cup of chocolate batter into the bottom of the pan, spreading it into a ring.
Insert Hearts: Stack frozen hearts in groups of 3 or 4 and place them upright in the pan with the points facing up. Fit them snugly to minimize gaps.
Fill & Bake: Pour the remaining chocolate batter into the pan, covering the hearts completely. Bake for 35 to 40 minutes, or until a toothpick inserted comes out clean.
Cool: Let the cake cool in the pan for 10 minutes, then invert onto a wire rack to cool completely.

Make the Chocolate Ganache

Heat the Cream: Place the chocolate chips in a heat safe bowl. Heat the heavy cream in the microwave for 1 to 1 ½ minutes until very hot but not boiling.
Combine: Pour the hot cream over the chocolate chips. Cover and let sit for 5 minutes.
Whisk: Remove the cover and whisk until smooth and glossy.
Finish the Cake: Pour the ganache over the cooled cake. Allow it to set for at least 10 minutes before slicing and serving.

Notes

Heart Cutter Size: Use a heart shaped cutter that fits comfortably inside the bundt pan with room to spare. Having multiple sizes can be helpful.
Color Placement: For the most visible heart design, place lighter or red tones on the outer edges and darker colors like purple in the center.
Freezing Tip: Freezing the cut hearts makes them easier to handle and helps prevent breakage during assembly.
Stacking Hearts: Stack hearts in groups of 3 or 4. Too many at once can create straight lines, while too few may allow batter to seep between layers.
Storage: Store the cake at room temperature for 3 to 5 days, similar to a standard boxed cake.

Nutrition