We wanted an angel food cake that would appeal to the masses, not just to those counting calories. To get an angel food cake recipe for a tall, perfectly shaped cake with a snowy white, tender crumb encased in a thin, delicate, golden crust, we experimented with egg whites. We found the key was the speed at which we beat the egg whites, starting at low speed just to break them up into a froth and increasing the speed to medium to form soft, billowy mounds. When large bubbles stop appearing…