Sarah Kieffer started banging sheet pans in ninth grade. She was going through “a cookie phase,” trying to find the perfect chocolate chip recipe, and one of them wasn’t working out. While most cookies spread in the oven, this one stayed put. “It was just this ball of dough that didn’t fall, so I hit the pan in the oven because I was mad,” she told me over the phone. “That helped.” The cookies deflated, thinned out, and spread more. Lifting the pan, then banging it down, forces cookies to breathe out all their hot air and become less puffy and cakey. It was an aha moment for Kieffer. She loved how pan-banging set the cookies’ edges, encouraged a gooey center, and, most of all, set off a wave of concentric ripples, like dropping a stone into a puddle. From then on, she “started incorporating it into almost every cookie recipe.” TO CHECK OUT ALL HER EXPERIMENTATION AND RECIPE, CLICK HERE.