Florida Key Lime Pie

This pie was born of necessity in the Florida Keys, where fresh milk was a fantasy and refrigeration a distant dream. Sometime in the late 1800s, Keys fishermen and sponge divers discovered that the acid in tiny Key limes would thicken sweetened condensed milk into a custard without any cooking at all. The chemistry was simple: citric acid denatures the milk proteins, creating a silky filling that sets firm in the icebox. No oven required until some later cook thought to add a crust.

The graham cracker base came later, probably in the 1930s when Nabisco's boxed crackers reached every corner store in America. Before that, Keys cooks used whatever they had. Some didn't bother with crust at all. But the graham version has become canon now, and I won't argue with it. The sweet, sandy crumbs provide the perfect counterpoint to that aggressive tartness.

Key limes are not Persian limes. This matters. They're smaller, seedier, more aromatic, with a floral quality that regular supermarket limes cannot replicate. If you can find them, buy twice what you think you need. They're temperamental little things, yielding maybe a tablespoon of juice each. If you cannot find them, bottled Key lime juice from Nellie and Joe's or Manhattan brand will serve you honestly. Many Keys natives use it themselves.