In a stockpot, place the chicken
(or meat) and stock, bring to a boil, lower the heat and cook until tender. Set chicken (or beef) and stock aside.
Toast chiles lightly, just until they give off aroma (avoid scorching), soak them in hot water for 20 minutes.
Boil tomatoes and tomatillos together until the tomatillos soften. Peel tomatoes (not the tomatillos) and place both in blender with chiles, spices, garlic, onion, avocado leaves and 1 cup of reserved stock.
Heat oil or lard in heavy stockpot. Strain blended mixture into stockpot using food mill or sieve. Cook, stirring constantly, for 10 minutes, adding more stock if needed to prevent sticking.
Place masa (or mixture of masa harina and water) in blender with 1 cup broth and blend well. Stir into tomato-chile mixture, stirring constantly as mixture thickens. Cook 15 minutes, adding enough broth (2 to 2-1/2 cups) to make a sauce that will coat the back of a spoon. Serve chicken or meat in a bowl with mole sauce and cooked vegetables (new potatoes, chayote, green beans) or serve shredded in empanadas or as a sauce for chilaquiles.