While I love baking, living in New York City doesn't lend itself to having a lot of storage space, especially in the kitchen. The baking shelf in my pantry is stocked very simply with basics and essentials. While I'd love to keep things like cake flour on hand, it just isn't practical since I don't use it on a regular basis. Instead I have room for one bulky sack of all-purpose flour.
Turns out you can actually get the benefits of baking with cake flour without having to buy it (and store it). All it takes are two common pantry items to make a cake flour substitute at home.
The Difference Between Cake Flour and All-Purpose Flour
The primary difference between cake flour and all-purpose (AP) flour is the protein content (which becomes gluten). The protein content of cake flour is about 8%, while the protein content of AP flour is about 10-11%. When you're making cakes, you want to use a flour that's lower in protein. It should have a little gluten for structure but not so much that it gets tough and chewy.
How To Make Cake Flour Substitute at Home
Whether you don't keep cake flour in the pantry or you've just run out, making a substitute is easy. All you need are two ingredients from the pantry — all-purpose flour and cornstarch.
Here's how to do it - Take one level cup of AP flour, remove two tablespoons, and then add two tablespoons of cornstarch back in.
1 cup AP flour - 2 Tablespoons AP flour + 2 Tablespoons cornstarch = 1 cup cake flour
Be sure to sift the flour to distribute the cornstarch well before using it in your cake batter. When added to all-purpose flour, cornstarch will inhibit the formation of gluten while also giving structure and 'sponginess' to your cake.
Other starches like arrowroot and potato starch can also be used, but our food science guru Harold McGee warns that cakes with these starches will cook more quickly and will often be more moist than those with cornstarch.
Updated from a post originally published March 2008.