INGREDIENTS
5
Egg whites, large
2 1/4 cups
All-purpose flour
2 tsp
Baking powder
1/2 tsp
Baking soda
1 3/4 cups
Granulated sugar
6 cups
Powdered sugar
5/8 tsp
Salt
2 tbsp
Vanilla, pure
1
Vanilla buttercream frosting
2 1/2 cups
Butter, unsalted
5 tbsp
Heavy cream
3/4 cup
Sour cream
3/4 cup
Whole milk