Also known as frijoles refritos. Absolute must with any mexican dish. Serving suggestion, topped with fresh Cheddar and tortilla chips. Please note that the cook time does not include soaking the beans overnight.
Soak the beans overnight, then drain. Place in a large pan with the quartered onion, the herbs, and chili. Pour over enough cold water to cover and bring to a boil. Reduce the heat, cover, and let simmer gently for 2 hours, or until the beans are very tender.
Drain the beans, reserving the cooking liquid, and discard the onion, herbs, and chili.
Place two-thirds of the beans with the cooking liquid into a food processor or blender and process until coarsely blended.
Heat the oil in a heavy skillet over medium heat. Add the chopped onion and cook for 10 minutes, or until soft and golden. Add the cumin and cook, stirring, for 2 minutes. Stir in the pureed and reserved beans and cook, stirring constantly, until the liquid reduces and the mixture thickens. Serve immediately.