If your recipe calls for cake flour and you don’t have any, it’s easy to make a suitable replacement with all-purpose flour and cornstarch. Here’s how.
The easiest way to accurately convert the all-purpose flour is to measure it in 1-cup increments using the spoon and sweep method and then replace 2 tablespoons with the cornstarch.
Stir the all-purpose flour. Spoon the flour into a 1-cup dry measuring cup until it is overflowing. Sweep the back of a butter knife or straight handle of a wooden spoon over the top of the cup to level the flour.
Remove two tablespoons of the flour and replace it with 2 tablespoons of cornstarch.