Ingredients
1 pinch salt
2 teaspoons vanilla
2 to 4 tablespoons milk
3 1/2 to 4 cups powdered sugar
16 tablespoons (2 sticks) unsalted butter, softened
Nonpareil sprinkles, for decorating (optional)
12 tablespoons (1 1/2 sticks) unsalted butter, softened
1 teaspoon salt
4 teaspoons baking powder
1 3/4 cups granulated sugar
1 vanilla bean, scraped
1 teaspoon vanilla
6 egg whites, room temperature
1 cup milk, room temperature
2 1/4 cups cake flour, plus more for preparing cake pans
Step by step
Heat oven to 350°F. Spray two KitchenAid® Professional-Grade Nonstick 8×2 Round Pans with baking spray. Line cake pan bottoms with parchment paper, then spray paper. Dust pans with flour; invert and rap pans to remove excess flour.
In a large bowl, stir milk, egg whites, vanilla and vanilla bean seeds until combined.
In a bowl of a KitchenAid® Classic Series 4.5-Quart Tilt-Head Stand Mixer with a flat beater attachment, stir cake flour, sugar, baking powder and salt until combined. Cut butter into cubes and add to bowl; stir on low speed 2 minutes until mixture resembles coarse crumbs.
Add milk mixture to flour mixture and beat on medium speed 2 minutes. Scrape sides of bowl and beat another 15 seconds.
Divide batter between prepared cake pans. Bake on center rack 30 to 35 minutes until a toothpick or cake tester comes out clean. Cool cakes in pans 5 minutes, then carefully invert cakes and transfer, flat-side down, to a cooling rack to cool completely, 1 to 1 1/2 hours.
Meanwhile, make the frosting: In a clean bowl of a KitchenAid® Stand Mixer with the flat beater attachment, beat butter on medium speed 3 minutes until soft, light and fluffy. Add 3 1/2 cups powdered sugar, 1/2 cup at a time, beating on high speed after each addition until just combined.
Add 2 tablespoons milk, plus vanilla and salt. Stir until combined.
Frosting should be a firm, yet smooth and spreadable consistency. If too soft, stir in remaining 1/2 cup powdered sugar 1 tablespoon at a time until firm. If too firm, stir in more milk 1 tablespoon at a time until soft.
Use a serrated knife to trim domed tops of fully cooled cakes to create a flat surface. Place one cake, cut-side up, on a cake stand or serving plate. Use an offset spatula to frost top of cake. Top with second cake, cut-side down. Frost sides and top of cakes. Decorate with nonpareil sprinkles, if desired.