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Funfetti Sheet Cake

A funfetti cake recipe that rivals any boxed funfetti mix. With homemade vanilla buttercream on top, you'll never pick up a cake mix again!
Prep Time30 mins
Cook Time30 mins
Total Time1 hr
Course: Dessert
Cuisine: cake
Servings: 20 servings
Calories: 361kcal


To make the cake:

  • 2 cups (240 grams) unbleached all purpose flour
  • 1 1/3 cups (264 grams) granulated white sugar
  • 1 tbsp baking powder
  • 1 tsp kosher salt
  • 3/4 cup (138 grams) vegetable shortening
  • 1 1/4 cups (284 grams) 2 % or whole milk
  • 1 tbsp vanilla extract
  • 3 (105 grams) egg whites
  • 1/2 cup (85 grams) rainbow sprinkles (plus more for sprinkling on top)

To make the frosting:

  • 20 Tablespoons (283 g, 1 1/4 cups) unsalted butter softened
  • 2 1/2 cups (284 grams) confectioners sugar (powdered or icing)
  • 2 Tablespoons heavy cream (or milk)
  • 2 teaspoons vanilla extract
  • 1/8 teaspoon kosher salt


To make the funfetti cake:

  • Preheat the oven to 350oF. Spray a 9x13 pan with cooking spray.
  • In the bowl of a stand mixer, fitted with a paddle attachment, combine the flour sugar, baking powder, and salt. Add the shortening and mix on medium speed until the mixture is combined. Add the milk and vanilla and mix on medium speed for 2 minutes, scraping the sides of the bowl as necessary.
  • Add the egg whites and continue mixing 1 to 2 more minutes, until very smooth. Stir in sprinkles.
  • Spread the batter evenly into the prepared pan. Bake for about 30 minutes until a toothpick inserted in the center comes out clean and top is lightly golden browned, and springs back when touched.
  • Allow the cake to cool before frosting. 

To make the buttercream frosting:

  • Combine the butter and confectioners sugar in the bowl of your stand mixer.
  • Mix on low speed at first, then increase the speed until combined.
  • Add in your heavy cream and vanilla extract, and mix on medium to high speed for 8 minutes until light and creamy.
  • If not using immediately, store in a container in the refrigerator until ready to use, mix again until light and fluffy.


  • Tools: 9x13 Pan (or 2 8-inch cake pans)| Stand Mixer | Sprinkles - Any rainbow sprinkles work, I really like these confetti ones
  • Unfrosted Cake At room temperature: You can make the cake up to 2 ahead of time. Cover the pan in plastic wrap. Just make sure it's completely cool before doing so. 
  • Frosted Cake (at room temperature) If you have frosted the cake, then be sure to cover it properly. It will be fine at room temperature for about 2 days. The frosting will lock the moisture in.
  • Baking as a layer cake: two 8-inch cake pans. Divide the batter evenly between the cake pans and bake for 20 to 25 minutes. 


Calories: 361kcal | Carbohydrates: 43g | Protein: 2g | Fat: 20g | Saturated Fat: 10g | Trans Fat: 1g | Cholesterol: 34mg | Sodium: 148mg | Potassium: 107mg | Fiber: 1g | Sugar: 33g | Vitamin A: 396IU | Vitamin C: 1mg | Calcium: 50mg | Iron: 1mg