INGREDIENTS
1
box white cake mix, 15.25 oz
1 cup
sugar
1 cup
all purpose flour
3/4 tsp
salt
4
egg whites
1 cup
milk
1/2 cup
buttermilk
1 cup
sour cream
2 sticks
butter, room temperature
1/2 cup
vegetable shortening (can be replaced with butter)
1 tsp
vanilla extract
3 cups
powdered sugar