Toast ancho, guajillo, and cascabel chiles in a heavy skillet until skins blister. Remove from skillet and stem, seed, and devein chiles. Set aside.
Place tomatoes and green tomatoes in a saucepan and bring to a boil. Drain and blend in blender or food processor and set aside.
In a large saucepan, heat corn oil over low flame. Cut the telera bread or 4 slices of white bread, into pieces and fry in the corn oil until golden brown. Add cinnamon stick, cloves, peppercorns, thyme, cumin, sesame seeds, peanuts, almonds, raisins, plantains, and walnuts. Stir ingredients together. Add more corn oil, to coat ingredients lightly. Add chopped roasted onion and minced roasted garlic. Continue to fry over low flame for about 20 minutes. Add blended tomato mixture. Remove from heat and set aside.
Place corn tortilla over open flame and cook until burnt and crispy. Cut up and set aside.
In a medium frying pan, fry roasted chiles in corn oil along with burnt tortilla pieces for a few minutes. Combine tomato/spice/nut mixture with chile mixture in large saucepan. Add chocolate piece and cook until melted over a low flame. Add about 1/2 cup chicken stock to mixture and stir. Place mixture into blender or food processor and puree until all ingredients have combined completely. More chicken stock may be added to smooth out sauce.
In a large saucepan, heat vegetable shortening. Cook the puree in the shortening, stirring constantly. Add more of the chicken stock until you achieve the right level of consistency that you'd like. Warm sauce for another 30 minutes over a low flame.
Recipe courtesy of Soledad Lopez