Preheat your oven to 350°F and grease two 8-inch round cake pans. Line the bottoms with parchment paper so the layers release cleanly—I learned this the hard way after my first cake stuck to the pan. This matters because broken layers won't hold the sprinkle pocket properly.

Cream the butter and sugar together for 2 minutes until the mixture turns light and fluffy. This creates tiny air pockets that make the cake tender instead of dense. I always scrape down the bowl halfway through because butter likes to hide in corners.

Add the eggs one at a time, beating for 20 seconds after each egg goes in. Whisk the vanilla extract into the milk separately, then alternate adding the dry ingredients and milk mixture to the butter mixture. This three-part method prevents lumps, which honestly saves so much frustration.

Divide the batter between the pans and bake for 48–52 minutes until a toothpick inserted in the center comes out with just a few crumbs. The tops should spring back lightly when you touch them. Cool the cakes in the pans for 10 minutes, then turn them out onto a wire rack to cool completely.

While cakes cool, whip the cold heavy cream with powdered sugar, cornstarch, and lemon juice until stiff peaks form. This takes about 3 minutes with an electric mixer. The cornstarch stabilizes the frosting so it doesn't weep during a hot kids summer afternoon—this trick gets forgotten constantly, and it makes all the difference.

Place the first cake layer on your serving plate and spread a thin frosting layer on top. Sprinkle half the rainbow sprinkles over that frosting, staying about an inch from the edges. Layer the second cake on top—this pocket design is what makes this patriotic pinata cake family recipe special because the sprinkles stay hidden and vibrant.

Frost the outside of the entire cake with the remaining frosting using an offset spatula or butter knife. If frosting cracks, add a tablespoon of milk and whip for 30 seconds. Press the white chocolate shavings into the frosting around the bottom edge, then sprinkle the edible glitter across the top.