Flour contains proteins that can cause a crust to turn a little leathery or tough. Cornstarch, on the other hand, is a pure starch, so chicken dipped in cornstarch stays super-light and crisp- it's the key to the texture of Korean fried chicken. Just as we do in our french fry recipe, we fry the chicken twice. The first time is to help it cook all the way through; the second is to crisp up the crust just before serving.
This recipe is excerpted from the new cookbook, "Serious Eats: A...Full Story