Bringing together English cooking methods with truly American products, American Cookery contains the first known printed recipes substituting American maize for English oats; and the recipe for Johnny Cake is apparently the first printed version using cornmeal. The book also contains the first known recipe for turkey. Possibly the most far-reaching innovation was Simmons's use of pearlash-a staple in colonial households as a leavening agent in dough, which eventually led to the development of modern baking powders.