Step 1

Preheat oven to 350°F (177°C). Grease and lightly flour three 9-inch cake pans.*

Step 2

Whisk the sifted flour, baking powder, baking soda, and salt together in a large bowl. Set aside. Using a handheld or stand mixer fitted with a paddle attachment, beat the butter on high speed until smooth and creamy – about 1 minute. Add the sugar and beat on high speed for 5 full minutes until creamed together fairly well. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed. On medium-high speed, add 1 whole egg at a time, beating well after each addition until all 4 whole eggs are mixed in. Set the 2 egg whites aside for now. Beat in the vanilla extract. Scrape down the sides and up the bottom of the bowl with a rubber spatula as needed.

Step 3

With the mixer on low speed, add the dry ingredients in three additions alternating with the buttermilk, beginning and ending with the dry ingredients, and mixing each addition just until incorporated. Do not overmix this batter. The batter will be smooth, velvety, and slightly thick. Vigorously whisk or beat the 2 additional egg whites until thick, foamy, and soft peaks form- about 3 minutes. Gently fold into the batter. Finally, fold the sprinkles into the batter. Spoon/pour batter evenly into each cake pan.

Step 4

Bake for around 25 minutes or until the cakes are baked through. To test for doneness, insert a toothpick into the center of the cake. If it comes out clean, it is done. Allow cakes to cool completely in the pans set on a wire rack. The cakes must be completely cool before frosting and assembling.

Step 5

In a large bowl using a hand-held mixer or stand mixer fitted with a whisk or paddle attachment, beat the butter on medium speed until creamy – about 2 minutes. Add confectioners’ sugar, cream, vanilla extract, and salt with the mixer running on low. Increase to high speed and beat for 3 full minutes. Add more confectioners’ sugar if frosting is too thin, more cream if frosting is too thick, or a pinch more of salt if frosting is way too sweet.

Step 6

First, using a large serrated knife, slice a thin layer off the tops of the cakes to create a flat surface. Discard (or crumble over ice cream!). Place 1 cake layer on your cake stand or serving plate. Evenly cover the top with frosting. Top with 2nd layer and evenly cover the top with frosting. Finish with the third cake layer and spread the remaining frosting all over the top and sides. I tinted extra frosting both pink (1 drop pink food coloring) and blue (1 drop blue coloring) and used a Wilton 1M tip to pipe it around the top edges. Decorate top of cake with sprinkles, if desired.

Step 7

Slice, serve, enjoy!