Confetti Party Cake

 

It occurred to me that I haven’t posted this Smitten Kitchen recipe for Confetti Party Cake, which is a tragedy because it is ah-ma-zing. It’s easy to make, it’s beautiful, it’s delicious – I dare you to find a flaw in this cake! We’ve made it for a few birthdays now, always to great acclaim. I’ve adapted the recipe to make a 9” layer cake by doubling the cake recipe and quadrupling the frosting recipe; the version below is mine. Note that you need the jimmy-type sprinkles here, not the non-pareil ones, as the latter would bleed too much.

For the cake 

1 cup (8 oz. or 4 sticks) lactose-free butter, at room temperature 

1 1/3 cups (260 grams) granulated sugar 

1 tsp. kosher salt 

4 large egg whites 

1 tsp. vanilla extract 

1 cup lactose-free buttermilk substitute (1-2 Tbsp. vinegar or lemon juice plus lactose-free milk) 

2 tsp. baking powder 

¼ cup (32 grams) cornstarch 

2 cups (260 grams) all-purpose flour 

½ cup rainbow sprinkles (see note above)

For the frosting 

2 cups (1 lb. or 4 sticks) lactose-free butter, at room temperature 

5 cups (600 grams) powdered sugar, sifted if lumpy 

¼ tsp. of fine salt 

2 tsp. vanilla extract, plus more to taste 

4 Tbsp. lactose-free milk or cream 

rainbow sprinkles for decoration

Preheat oven to 350 °F. Line the bottom of two 9-inch round cake pans with parchment paper and coat the bottom and sides with nonstick spray or butter.

Beat butter, sugar, and salt together in a medium bowl. Add egg whites, one at a time, beating until combined and slightly fluffy. Add vanilla and buttermilk and beat to combine. The mixture will instantly look like cottage cheese and you will be sure it’s ruined, but I promise it is not. Add baking powder and cornstarch and beat very well to combine. Scrape down sides of bowl and beat one second more. Add flour and mix just until it disappears. Use a rubber spatula to gently fold in sprinkles.

Spread batter in prepared pans and smooth the top. Bake for 20 minutes, or until a toothpick inserted into the center of the cake comes out batter-free. Let cool in pans on cooling rack for 5 minutes, then run a knife around the sides to loosen the cake, flip it out onto the cooling rack, and slide the cooling rack into the freezer until cake is cool, about 10 to 15 minutes. (Honestly, I just let it come to room temperature on its own.)

While the cake cools, beat butter, sugar, salt and vanilla until fluffy, then add milk or cream 1 tablespoon at a time and beat until smooth. Once cake is fully cool, transfer it to a serving plate. Spread frosting on top — you’ll have more than enough, so if you need to set some aside for small decorations or tinting and writing on the cake, this won’t be a problem. Finish with sprinkles. Share with friends.