The recipe I posted yesterday called for cake flour, which, even as a baker, isn't something I usually keep on hand (I know, I know, shame on me). But! Luckily, I can easily make my own with items I always have - regular all-purpose flour and corn starch.
It's simple, for every cup of cake flour required use one cup of all-purpose flour, minus two tablespoons, and then replace those with two tablespoons of cornstarch. Sift half-a-dozen times and use! Easy, peasy.
Example: the Red Velvet Cake from yesterday calls for 4 1/2 cups of cake flour, so I used 4 cups of flour and 1/2 cup of cornstarch and sift, sift, sift!