INGREDIENTS
3
and 3/4 cups (431g) sifted all-purpose flour1 (measured correctly)
3/4 tsp
baking powder
3/4 tsp
baking soda
1 tsp
salt
1
and 1/2 cups (3 sticks; 345g) unsalted butter, softened to room temperature
1
and 3/4 cups (350g) granulated sugar
4
large eggs, room temperature
2
large egg whites, room temperature
3 tsp
pure vanilla extract
1
and 1/2 cups (360ml) buttermilk, room temperature2
3/4 cup
rainbow sprinkles3
1
and 1/2 cups (3 sticks; 345g) unsalted butter, softened to room temperature
6
cups (700g) sifted confectioners' sugar
1/3 cup
heavy cream
3
teaspoons (15ml) pure vanilla extract (or use clear imitation vanilla extract for stark white frosting)
1/8 tsp
salt
optional: additional sprinkles for garnish