This cake is so much fun they put it right in the name! Rainbow sprinkles give this cake an undeniably festive flair. Kids and grownups alike will love this delicious, multicolored cake.
Technique tip: To make party-size cake bites, skip icing the sides of the cake and use a 4-inch ring mold to cut 6 rounds out of the assembled cake. Then cut each round in 8 wedges. This will give you 48 miniature slices of cake. Save the scraps for snacking!
- 4 sticks butter, softened
- 3⅓ cups sugar
- 3 tablespoons vanilla extract
- 1½ teaspoons coarse salt
- 4⅓ cups cake flour
- 2 teaspoons baking powder
- 12 large egg whites
- 1½ cups milk
- 3 cups rainbow sprinkles
Funfetti buttercream (makes about 4 cups)
- 1 pound softened butter
- 3 cups sifted powdered sugar
- 1 tablespoon vanilla extract
- 2 teaspoons salt
- 1 cup rainbow sprinkles
For the cake:
1. Preheat oven to 325°F. Grease a 13- by 18-inch sheet pan with parchment paper.
2. In the bowl of a stand mixer fitted with a paddle attachment (or in a bowl using a hand mixer) mix the butter, sugar, vanilla and salt.
2. In a separate bowl, mix the flour and baking powder.
3. With the mixer on low speed, slowly add the flour mixture to the butter mixture and mix until smooth.
4. Add egg whites and mix until well incorporated. Scrape down the sides of the bowl. Add the milk and mix until smooth. Stir in rainbow sprinkles.
5. Pour the batter onto the prepared sheet pan.
6. Bake until cake pulls away from sides of pan, about 12-15 minutes.
7. Remove the cake from the oven and let cool completely in the sheet pan.
For the frosting:
In a stand mixer fitted with the paddle attachment (or in a bowl using a hand mixer) beat the butter and sugar together until smooth. Add in the vanilla, salt and sprinkles and beat until light and fluffy.
Cut the cake in half crosswise. Set one half aside and ice the other half with some of the Funfetti frosting. Place the other cake half on top and ice top and sides. Let chill in the refrigerator for at least an hour before serving.