½cup(1 stick or 113 g) unsalted butter, room temperature
1 ½cups(300 g) granulated sugar
3large eggs, room temperature
⅓cup(75 g) full-fat sour cream (or plain yogurt), room temperature
1Tablespoonpure vanilla extract
1cup(240 mL) buttermilk, room temperature
½cuprainbow sprinkles/jimmies, plus more for decorating
Buttercream Frosting
1 ½cups(3 sticks or 339 g) unsalted butter, room temperature
3 ¾cups(450 g) confectioners' sugar
1Tablespoonpure vanilla extract
2-3Tablespoonsmilk
Pinch of salt
Instructions
Funfetti Cake
Preheat oven to 350° F. Grease three 6-inch round cake pans and set aside. Pro tip: use my magic cake pan release for flawless cakes.
Whisk together flour, baking powder, baking soda and salt. Set aside.
In the bowl of a stand mixer fitted with a paddle attachment, beat the butter and sugar on medium high speed until light and fluffy, about 3 minutes.
Add eggs one at a time, beating well after each addition. Scrape down the sides and bottom of the bowl as necessary. Add the sour cream and vanilla, and mix just until combined. Scrape bottom and sides of the bowl as necessary.
With the mixer on low, alternate adding the flour and buttermilk. Gradually add about one third of the flour mixture followed by half of the buttermilk. Repeat. Add remaining flour mixture and mix just until combined (avoid over mixing).
Using a silicone spatula, stir in the sprinkles by hand making sure to scrape the bottoms and sides of the bowl.
Divide batter among prepared pans (each of my pans had about 410 g of batter). Tap pans gently against the countertop to remove any air bubbles. Bake cakes at 350° F for 25 to 30 minutes or until a toothpick inserted in the center comes out with little to no crumbs. Allow cakes to cool in the pan for 15 minutes before removing them and transferring to a wire rack to cool completely. Prepare frosting.
Buttercream Frosting
In the bowl of a stand mixer, beat the butter on medium high speed until fluffy (about 5 minutes). With the mixer on low, gradually add confectioners' sugar and beat until incorporated.
Increase speed to medium and add the vanilla and 1 Tablespoon milk. Check consistency. If the frosting is too thick to spread, add another 1 to 2 tablespoons of milk. Taste and add salt if needed to offset sweetness.
Assembly
Level the cakes if necessary by cutting off the domed top with a serrated knife. Place one round cake on a cake stand or plate. Evenly spread a thick layer of frosting on top. Place another cake round on top and add another layer of frosting. Top with the third layer.
Frost a crumb layer. Spread a thin layer of frosting around the sides and top of the cake. This will catch all the crumbs to they won't spread on the final layer of frosting. Place cake in the refrigerator for 30 minutes (or the freezer for 10).
Frost the cake with remaining frosting. An offset spatula works best for this. If desired, pipe more frosting on top for decoration and add additional sprinkles. Slice and serve!
Notes
Buttermilk substitute: Add 1 Tablespoon distilled white vinegar to a liquid measuring cup. Add whole milk and fill to the 1 cup measure. Stir and let the mixture sit for 5 minutes before using in the recipe.Greasing the pans: Try my magic cake release paste for guaranteed clean release from the pans!Double layer: Use two 8-inch rounds. Baking time will be 30 to 35 minutes.Note on frosting: This recipe makes just enough frosting for the cake. If you'd like extra for decorating, increase amounts to the following: 2 cups butter, 5 cups confectioner's sugar, 1 Tablespoon plus 1 teaspoon vanilla.Store at room temperature for up to three days. Loosely wrap the cake in plastic wrap. If in a warmer climate, store in the refrigerator.Freeze for up to 3 months. If frosted, flash freeze the cake for 1 hour to set, then wrap in a double layer of plastic wrap. Defrost in the refrigerator before serving.High altitude adjustments : The recipe above was written for sea level. To make adjustments for high altitude (Denver, CO; 5,280 ft): Decrease baking powder by 1/2 teaspoon. Decrease granulated sugar by 2 Tablespoons. Add an extra 2 teaspoons buttermilk. Increase oven temperature to 360 F. Check cakes at 25 minutes.