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Funfetti Sheet Cake

Fluffy vanilla cake with creamy vanilla buttercream and funfetti sprinkles

Prep Time 45 minutes
Cook Time 45 minutes
Cooling/Decorating Time 1 hour
Total Time 2 hours 30 minutes
Servings 20 servings
Author Katie

Ingredients

Funfetti Sheet Cake

  • 1/2 cup (or 1 stick) unsalted butter, room temperature
  • 1/4 cup vegetable oil
  • 1 cup granulated sugar
  • 3 large whole eggs
  • 1 large egg yolks
  • 1 1/2 cups cake flour (or 1 1/3 cup ap flour & 4 1/2 tsp cornstarch)
  • 1 teaspoon baking powder
  • 1/2 teaspoon salt
  • 1/2 cup buttermilk
  • 1 teaspoon vanilla extract
  • 1/3 cup confetti sprinkles

Vanilla Buttercream

  • 1 cup unsalted butter, room temperature
  • 1/2 teaspoon salt
  • 1 teaspoon vanilla extract
  • 3 3/4 cups powdered sugar, sifted
  • 1-2 Tablespoons heavy cream
  • brite purple gel food coloring
  • confetti sprinkles

Instructions

Funfetti Sheet Cake

  1. Preheat the oven to 325 °F. Spray the baking pan with non-stick spray, line the bottom of each pan with parchment paper and spray again. Set aside.

  2. In a medium-size bowl, whisk and stir together the flour, baking powder, and salt. Set aside.

  3. In the stand mixer bowl fitted with a paddle attachment, beat the butter, oil, and sugar on medium-high for 5 minutes.

  4. Add the eggs, one at a time to the stand mixer bowl and beat on medium until well incorporated.

  5. Turn the mixer on low and add the flour mixture to the butter mixture until fully incorporated.

  6. Pour in the buttermilk and vanilla extract. Mix on medium for another 30 seconds and scrape down the sides of the bowl.

  7. Fold the confetti sprinkles into the cake batter.

  8. Add cake batter to the prepared baking pan and bake for about 35-40 minutes or until a toothpick inserted into the center of each cake comes out clean or with just a few moist crumbs.

  9. Remove cakes from the oven and let cool completely until room temperature.

Vanilla Buttercream

  1. In the stand mixer bowl fitted with the paddle attachment, beat the butter until light and fluffy, about 2 minutes.

  2. Turn the mixer to low and add the salt and vanilla.

  3. Next, gradually add powdered sugar, followed by the cream. Add your choice of gel food coloring. Mix on medium-high speed for about 5 minutes, until light and fluffy. Scrape down the sides of the bowl.

  4. Before using, turn the mixer on low and mix for 2 minutes to push out any air bubbles or use a rubber spatula to push out the air bubbles. (You may need to repeat this step when frosting the outside of the cake).

Assemble

  1. Begin with a cooled sheet cake and add the whipped buttercream over the top. Use an offset spatula to spread out the buttercream and evenly cover the cake.

  2. hen add the confetti sprinkles. Serve at room temperature and enjoy.

Recipe Notes

  • Read through all the ingredients and instructions so you can get a better idea of how much time and what you need to make this cake.
  • A single batch of this cake recipe makes three, 6-inch round cake layers. Double the cake recipe to make enough cake batter for three, 8-inch cake layers.
  • In this cake recipe, you need 1 cup buttermilk; if you don't have any buttermilk on hand, you can easily use 1 cup whole milk mixed with 1 Tablespoon lemon juice or white vinegar to make your own. 
  • To make cake flour at home, mix 2 ¾ cups all-purpose flour and ¼ cup cornstarch. Sift or whisk together to get rid of any lumps. 
  • Be careful not to overmix this cake batter, or else the cake will come out dense. Mix until all ingredients are well incorporated.
  • You can bake the cake layers ahead of time. Wrap the cake layers in plastic wrap and freeze up to one month. 
  • You can make the buttercream a day ahead and refrigerate them overnight. Then take them out to come back to room temperature. Make sure the buttercream is at room temperature before re-whipping.