Trim the fat, gristle and connective tissue from the meat. Fry the trimmings in a large (3-4 quart) stockpot until about 2 tablespoons (for 6 servings) of fat have been rendered. Discard the trimmings. Add oil to the fat in the pan. Set aside. Cut the meat into 1 1/2" cubes. Set aside. Mince the garlic, onion and chiles together. Peel and pulp the tomatoes. Add to the onion mixture. Heat the fat in the stockpot. Sear the meat over high heat until browned on all sides. Reduce heat. Add the tomato and onion mixture. Add all the remaining ingredients except the tortillas. Cover. Simmer until the meat is tender and the liquid becomes a rich sauce (1 1/2-2 hours). Adjust seasonings. Serve with tortillas. NOTE: The meat filling can be spooned onto the tortillas.