Brown onion lightly in 3 tablespoons of fat in 10-inch frying pan. Add the beans and mash well (using potato masher or wooden spoon). Stir continuously until mixture is dry and fat is absorbed. Heat remaining fat (3 tablespoons) in a frying pan; add beans and continue to fry and stir until beans are dry enough to shake loose from the pan. Serve with tortillas.

Recipe adapted from The Cookbook of the United Nations.