Sweet potatoes in two colors grew in Peru, Central America, and the West Indies when Columbus came, tasted, and approved. One was pale yellow and the other dark orange. The Arawakan Indians called these tubers batatas and Columbus was happy to transport tuber and name back to the Old World to the eternal confusion of botanists and cooks. The Old World already knew of another exotic tuber, this one native to Asia and Africa, which was also sweet in taste, varied in color, and elephantine in size. So substantial was this family of tubers (Dioscorea bulbifera) that West Africans called it by their verbs “to eat”—njam, nyami, djambi—and so yam came to mean any nutritious sweet-tasting root. Botanically, sweet potatoes and yams are as unrelated as apples and oranges, but we are eaters first and the language of eaters continues to call the New World sweet potato “yam,” as it has for four centuries.

Such linguistic niceties do not encumber the annual Yambilee Festival at Opelousas, which awards prizes to the year’s best yam recipes. Heavy favorites are yams turned into a sweetened purée, then souffléed or baked in a crust, a cake, or a quick bread like biscuits or pone. The yam bread tradition goes back to the Picayune, which calls pain de patates “a delicious Creole bread,” only this one leavens yam purée with yeast to produce a beautiful saffron-colored loaf, unsweetened with any sugar but its own. The easiest way to make yam purée is to bake yams with their skins on until they are soft (an hour at 400°); when they cool, peel them and mash the flesh with a fork or purée in a processor.