Flour

Flour is the single most important ingredient in cake baking. The type of flour used, particularly its protein content and whether it is bleached or unbleached, is critical to the outcome. There are essentially three types of flour I use in this book. The two that I use most often are bleached cake flour and bleached all-purpose flour. Bleaching is critical for cakes made with unmelted butter because it roughens the surface of the flour grains, helping them to keep the butter in suspension and improving gelatinization. If unbleached flour is used, the cakes will dip in the center soon after removal from the oven and some of the butter will have settled on the bottom of the cake, resulting in an unpleasant flavor and texture. (For alternatives to bleaching, see "Kate Flour".)