Flour and Leaveners

All-purpose flour has a moderate protein level (9 to 12 percent). We prefer unbleached flour over bleached because we've found that bleached flour sometimes carries off-flavors that can be detected in simple recipes like bread or biscuits. If you use a higher protein all-purpose flour (such as King Arthur, with 11.7 percent protein) in our recipes, the results may be slightly drier and chewier. You can lower the protein content of higher protein all-purpose flour by replacing 1 tablespoon of flour per cup with 1 tablespoon of cornstarch. We use all-purpose flour for the cheesecake crust in this class—the starch granules get coated in butter, thereby preventing the graham cracker mixture from absorbing too much moisture via the filling, turning the crust soggy.

Bread flour has a high protein level (12 percent or above) and is often labeled "made for bread machines." The high protein content ensures strong gluten development and a sturdy batter or dough, which translates to good flavor and chewy texture. We use bread flour for the cupcakes in this class to give them enough structure to hold on to the ganache filling and not fall apart when eaten.

Cake flour has a low protein level (6 to 8 percent) and delivers delicate, fine-crumbed cakes and light, airy biscuits. Not all cakes require cake flour and we call for it only where we feel it delivers decidedly better results than all-purpose flour. You can also approximate cake flour by mixing cornstarch with all-purpose flour. For each cup of cake flour, use 7/8 cup all-purpose flour mixed with 2 tablespoons cornstarch. We use cake flour in the fluffy yellow layer cake in this class to produce a fine, tender crumb.

Baking soda provides lift to cakes and other baked goods. When alkaline baking soda meets up with an acidic ingredient (such as sour cream, buttermilk, or brown sugar), carbon and oxygen combine to form the gas carbon dioxide. The tiny bubbles of carbon dioxide then lift up the dough. In addition to its leavening powers, baking soda also promotes browning. The buttermilk called for in the yellow layer cake recipe in this class reacts with the baking soda to provide extra lift, making the cake light and airy.

In addition to cornstarch, an inactive ingredient, baking powder has two active ingredients: baking soda and an acidic element. Since carbon dioxide gas is produced when baking soda comes in contact with a moist, acidic environment, cooks use baking powder rather than baking soda when there is no natural acidity in the batter. There are two kinds of baking powder. Single-acting baking powder has only one acid combined with the baking soda—a quick-acting acid that begins to work when liquid is added to the batter. Double-acting baking powder (like most supermarket brands) has two acids added to the baking soda. The second acid begins to work only when the dish is put in the oven, after the temperature has climbed above 120 degrees. We recommend using double-acting baking powder in all recipes. Unlike baking soda, baking powder doesn’t need an acidic agent to activate; we often use it in conjunction with baking soda for the ideal lift.