Ingredient Substitution: potato starch and matzo cake meal for cake flour

I found this info years ago in an article on adapting cake recipes for Passover. Generally speaking, if a cake recipe (i.e., not puff pastry or shortbread) requires less than 1 cup flour, you can substitute potato starch for that flour, and make exactly the same pastry. If anything, you'll end up with a lighter cake.

If the cake recipe calls for a butter and sugar batter, the butter will make it heavier, and it will need something more than potato starch to support it. In that case, you can make exactly the same cake by substituting 1/2 cup matzoh meal for each 1 cup flour, and adding 1 extra egg. Always use unsalted butter, preferably at room temp. Eggs should always be a t room temperature too.

I agree. I would only do a cake meal swap for flour when the recipe calls for a slight amount of flour-1/2 cup or less. Because cake meal has a very ditinct flavor, when swapping it in such large quantities, it would change the taste and texture of the cake. And potato starch is a different creature all together.

You're better off using a recipe meant for Passover use. You could take the appealing aspects of the cake recipe and incorporate them in the other recipe.