Place your frozen watermelon into a blender and add in half of the requested milk.
Blend until smooth, adding in a little more milk as needed to get to your desired consistency.
Add in the honey or sweetener and blend again to combine.
Divide the milkshake into two drinking glasses and serve. Top with whipped cream if desired.
Notes
You can adjust this watermelon milkshake recipe to your own tastes by adding in more or less milk for a thicker/thinner drink.It helps to have the watermelon cut into smaller chunks before freezing. I recommend slicing the watermelon and placing it on a baking sheet for a few hours to freeze solid before transferring to a bag or airtight container as this helps to prevent the pieces from sticking together.If you can use ice cream or frozen yogurt to help thicken the drink and make it stretch even further. Start by adding 1 cup of ice cream and then taste and add more as desired.