Why you should use cake flour
Cake flour is high in starch and low in protein. It’s the proteins in all-purpose flour that cause a cake to be tough if the batter is overworked, and cake flour helps to make sure that doesn’t happen. Use cake flour in a recipe when it calls for it and you’ll get tender cakes every time.
If you don’t have cake flour on hand, substitute 1 cup minus 2 tablespoons of all-purpose flour for 1 cup of cake flour.