Cake flour is a low protein flour that helps produce a tender texture in baked goods, and is often called for in pies, biscuits, and cakes. It is sold in pretty small quantities, generally a 3-pound box, which anybody can use up, given a little imagination and initiative. But for only a third of a cup, you can certainly substitute all-purpose flour in your recipe.

All-purpose flour absorbs water better than cake flour, so you may want to add a little extra moisture to the recipe to get the right consistency in your batter, or cut the amount of flour by a half-teaspoon or so.