Step 1

Preheat oven to 350°F (177°C). Grease four 9-inch cake pans, line with parchment paper rounds, then grease the parchment paper. Parchment paper helps the cakes seamlessly release from the pans. (If it’s helpful, see this parchment paper rounds for cakes video & post.)

Step 2

Whisk the 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. 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.

Step 4

There will be 8 cups of batter total– transfer half of it to another bowl. Stir in 1/3 cup sprinkles into half and the food coloring into the other half. Pour/spread batter evenly into prepared cake pans.

Step 5

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 6

Use the video above for a visual of this step. Using a 6-inch round cookie cutter (it’s large!), cut a circle into each cooled cake. Using a 3-inch round cookie cutter, cut a circle out of the 6-inch circle. You will have 4 3-inch circles, 4 6-inch circles (the outlines), and 4 9-inch circles (which are just a thin outline of cake since the centers are missing).

Step 7

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 8

Again, use the video above for a visual of this step. Place one blue 9-inch outline of cake onto a serving plate or cake stand. Fill with a funfetti 6-inch circle, then a blue circle. Spread frosting evenly on top. Repeat with next layer: 9-inch funfetti filled with 6-inch blue then 3-inch funfetti. Spread frosting evenly on top. Repeat next 2 layers. Spread the remaining frosting all over the top and sides. Decorate top and sides of cake with extra sprinkles, if desired.

Step 9

Refrigerate the cake for at least an hour before slicing and serving. The time in the refrigerator ensures a neater cut!

Step 10

Cover and store leftover cake at room temperature for 1-2 days or in the refrigerator for up to 1 week.