Confetti Party Cake

This past weekend marked my daughter’s (gasp) 4th birthday.  What does every little kid want for their birthday?  A cake filled with sprinkles.  Dots of funfetti colours throughout the cake, topped with icing and more sprinkles really screams “kid birthday”!  And while it is filled with artificially coloured sprinkles (they are necessary to really achieve the colour needed), this is a homemade white cake that is as moist and light as you could hope for.  Add in a buttercream frosting and everyone will declare it a delicious party.

I am usually in charge of cakes for most of our family occasions.  The great thing about a cake is that it can easily be made in advance and frozen, and in fact it is easier to ice from frozen.

Make sure to frost the cake with a small “base layer” and leave it in the fridge to set.  This ensures a crumb-free icing!

I made a double layer 8 x 8 square cake, but this recipe also works as a more traditional double layer 9″ round cake.  You can easily halve the recipe and make 1 layer cake for small occasions (or a random Wednesday, I need cake day).  Trying to feed a crowd?  You can increase the measurements by half (yes you may need to do some math here) and cook it in two 9 x 13″ cake pans.

Confetti Party Cake

Cake
1 cup (330 g) salted butter, at room temperature
1 1/3 cup (260 g) granulated sugar
1 tsp kosher salt
4 large egg whites
1 tsp vanilla extract
1 cup (240 ml) buttermilk
2 tsp baking powder
4 Tbsp (32 g) cornstarch
2 cup (260 g) all-purpose flour
1/2 cup rainbow sprinkles

Preheat the oven to 350F. Line the bottom of two 8 x 8 square or 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- this is normal. Add the baking powder and cornstarch and beat very well to combine. Scrape down the sides of the bowl and beat again to combine. Add flour and mix just until if disappears. Use a rubber scraper to gently fold in sprinkles.

Spread batter in the 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 the pan on a cooling rack for 5 minutes, then run a knife around the side 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.

Frosting
1 cup (230 g) salted butter, at room temperature
2 1/2 (300 g) powdered sugar, sifted if lumpy
1 tsp vanilla extract, plus more to taste
2 Tbsp cream, plus more if needed to thin
rainbow sprinkles for decoration

Beat butter, sugar, and vanilla until fluffy. Add the cream and beat until smooth. The frosting should still be stiff but spreadable. Add more cream if necessary to achieve that consistency.

Spread a thick layer of frosting on the bottom layer and add the top cake layer.  Frost the entire cake with a thin layer of frosting and refrigerate for at least 15 minutes to allow the frosting to “set”.  This will prevent crumbs in the frosting.  Cover with the remaining frosting and decorate with sprinkles, or however you like.

Note: This amount of frosting was just enough to cover a two layer 8 x 8 layer cake with writing.