This delightful Florentine Carnival cake is a sweet flatbread built from a yeasted dough, one that incorporates honey, vanilla, orange juice and orange zest. It's also enriched with lard. During Carnival season, this cake appears at bakeries, pastry shops and bars throughout Florence. Some are filled with whipped cream, chocolate or custard; most are showered with powdered sugar. The dough needs about two hours to rise, so plan accordingly.