Favorite White Layer Cake

and 1/2 cups (275g) sifted cake flour* (measured correctly)

baking powder

baking soda

salt

(1.5 sticks; 170g) unsalted butter, softened to room temperature

and 3/4 cups (350g) granulated sugar

large egg whites, at room temperature

sour cream, at room temperature*

pure vanilla extract (yes, Tbsp!)

whole milk, at room temperature*

and 1/4 cups (2.5 sticks; 287g) unsalted butter, softened to room temperature

 cups (580g) sifted confectioners' sugar

heavy cream

 teaspoons pure vanilla extract (or use clear imitation vanilla extract for stark white frosting)

salt

sprinkles for garnish