Heat the oil and fry the onion, bell pepper, garlic and fresh chili for 5 minutes. Stir in chili powder, ground cumin and stir before adding stock or water, epazoe and a grinding of pepper. Cook for 50 minutes, addng more water if necessary.
When beans are tender, salt them to taste. Mash 1/4 of the mixture and return to pan. Add sugar and serve hot with cheese sprinkled on top. Serve with, e.g., long-grain rice.