One-Egg Cake

Creaming butter and sugar incorporates air bubbles that expand during baking, creating lift. The single egg provides just enough protein structure to support the crumb without making it tough. Sifting the flour with baking powder ensures even distribution of the leavener, preventing pockets of bitter taste and ensuring uniform rise. Adding flour last and beating well develops just enough gluten for structure while the chemical leavening does most of the work.