To make sure that the breasts cook at the same rate, purchase two similarly sized whole breasts (not split breasts) with skins fully intact. Whole chicken breasts weighing about 1 1/2 pounds work best because they require a cooking time long enough to ensure that the skin will brown and crisp nicely. If you do not own a broiler pan, use a roasting pan fitted with a flat wire rack. This recipe can easily be increased by 50 or 100 percent. If you do increase it, just make certain not to crowd the chicken breasts on the broiler pan, which can impede the browning and crisping of the skin.