In Oaxaca, black beans are a part of almost every meal. Though they sometimes are served whole, we especially liked the balanced, complex flavor and smooth, velvety consistency of refried black beans. We got a lesson in the importance of the daily basic from Rodolfo Castellanos, Oaxaca native and winner of Top Chef Mexico, and his mother. Lard gives these beans a rich meatiness, but coconut oil is a good vegetarian substitute. For a quicker version, see our pressure cooker variation. The beans can be stored in an airtight container in the refrigerator for up to a week. We liked this topped with cotija and fresh cilantro.