How to soften butter quickly, and why it matters for your baking

Why it matters. Many cake and cookie recipes rely on the creaming method, in which fat and then fat and sugar are beaten until light and fluffy. This process incorporates air, with sugar being particularly efficient at introducing and trapping air among the fat (which is often butter, but can also be shortening). “If you keep the fat cool, and beat the fat alone and the fat-sugar mixture sufficiently long to incorporate massive amounts of fine air bubbles, this method will produce a light, well-aerated cake,” Shirley Corriher says in “BakeWise: The Hows and Whys of Successful Baking.” (While many cookies use the creaming method, too, Corriher says it’s not quite as integral to successful cookies as cakes).