# Components:
→ Cake
01 - 2 1/2 cups all-purpose flour
02 - 2 1/2 teaspoons baking powder
03 - 1/2 teaspoon fine salt
04 - 3/4 cup unsalted butter, room temperature
05 - 1 3/4 cups granulated sugar
06 - 4 large eggs, room temperature
07 - 1 tablespoon vanilla extract
08 - 1 cup whole milk, room temperature
09 - 1/2 cup rainbow jimmies-style sprinkles (not nonpareils)
→ Champagne buttercream
10 - 1 cup unsalted butter, room temperature
11 - 4 cups powdered sugar, sifted
12 - 1/4 cup champagne or sparkling wine, room temperature (substitute additional milk for nonalcoholic)
13 - 1/2 teaspoon vanilla extract
14 - Pinch of fine salt
→ Decoration
15 - Additional rainbow sprinkles, as needed
16 - Edible glitter or sugar pearls (optional)
# Directions:
01 - Preheat oven to 350°F. Grease and line two 9-inch round cake pans with parchment paper; set aside.
02 - Whisk together the flour, baking powder and salt in a medium bowl until evenly blended; set aside.
03 - Using a stand mixer fitted with the paddle (or a hand mixer), beat the butter and granulated sugar on medium-high speed until pale and fluffy, about 3 minutes.
04 - Add the eggs one at a time, mixing well after each addition. Scrape the bowl and mix in the vanilla extract until combined.
05 - With the mixer on low, add the dry ingredients in three additions, alternating with the milk in two additions, beginning and ending with the flour mixture; mix until just combined.
06 - Gently fold the rainbow sprinkles into the batter with a rubber spatula to avoid excessive color bleed.
07 - Divide the batter evenly between the prepared pans and smooth the tops with an offset spatula or spoon.
08 - Bake for 28–32 minutes, or until a toothpick inserted in the center comes out clean. Cool in the pans for 10 minutes, then invert onto cooling racks and cool completely.
09 - Beat the butter on medium speed until creamy. Gradually add the sifted powdered sugar, 1 cup at a time, mixing on low. Add the champagne, vanilla and salt, then increase speed and beat until light and fluffy, about 3–4 minutes. Adjust consistency with a teaspoon of milk if too stiff.
10 - Place one cooled layer on a serving plate or cake stand. Spread an even layer of buttercream across the top, then place the second layer on top and crumb-coat the sides and top.
11 - Chill briefly if needed, then apply a final smooth layer of buttercream. Finish with additional sprinkles and optional edible glitter or sugar pearls.
