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Funfetti Layer Cake

Funfetti layer cake is a moist, tender white cake full of rainbow sprinkles and frosted with the most decadent white chocolate buttercream.
5 from 5 votes
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Prep Time 30 minutes
Cook Time 35 minutes
Decorating Time 1 hour
Course Dessert
Servings 10 slices

Ingredients
 

For the Funfetti Cake

  • ½ cup + 2 tablespoon unsalted butter, softened
  • 1 ½ cups granulated white sugar
  • 1 tablespoon vanilla bean paste
  • 4 egg whites, at room temperature
  • ¾ cup buttermilk, at room temperature
  • ½ cup sour cream, at room temperature
  • 2 ¼ cups all purpose flour
  • 1 ½ teaspoon baking powder
  • ¼ teaspoon baking soda
  • ½ tsp salt
  • ½ cup rainbow jimmies

For the White Chocolate Buttercream

  • 2 cups unsalted butter, softened
  • 8 oz. white chocolate, melted and slightly cooled
  • 2 ½ cups powdered sugar, sifted
  • ¼ cup rainbow jimmies for decorating
  • ¼ cup rainbow nonpareils for decorating

Instructions
 

For the Funfetti Cake

  • Preheat oven to 350 degrees. Spray 3 6" cake pans with non stick spray and place a parchment paper round in the bottom of each pan.
  • In a large bowl cream the softened butter and granulated sugar together.
  • Add in the egg whites and vanilla bean paste and mix until smooth, about 1 minutes.
  • Add in the buttermilk and sour cream and combine.
  • In a separate bowl whisk together the flour, baking powder, baking soda and salt.
  • Add the dry ingredients to the wet ingredients and mix the batter is smooth.
  • Mix in the rainbow jimmies.
  • Divide the batter evenly between the cake pans.
  • Bake the cakes for 32-36 minutes, or until a toothpick comes out clean from the centers with just a few moist crumbs.
  • Let the cakes cool in their pans for 5 minutes, then transfer them to a cooling rack to completely cool.

For the White Chocolate Buttercream

  • Add the softened butter to a large bowl and mix with an electric mixer until pale in color and fluffy, 5-10 minutes.
  • Then add in the melted and slightly cooled white chocolate and mix until combined. You'll want to make sure the white chocolate is just about room temperature, but still completely melted. If it's too warm the butter will melt and if it's too cold it can cause clumps of chocolate to end up in the frosting.
  • Add in the powdered sugar a little at a time and mix until it is all combined and the frosting is light and fluffy.

Assembling the Cake

  • One the cakes are cooled fill each layer and frost the outside with white chocolate buttercream. Add sprinkles to the top and outside of the cake. See the blog post above for all the step by step instructions along with photos.

Notes

Store leftovers in an airtight container for up to three days.
Tried this recipe?Let us know how it was!