1(1-inch-thick) slice pan de yema, pan de muerto, challah, or other egg-based bread, cut into large pieces
1small ripe plantain, peeled and cut into 1/2-inch-thick slices (about 1 cup)
1/2cupsesame seeds (about 2 oz)
FOR FINISHING MOLE
2tablespoonslard or vegetable oil
4 ozMexican chocolate, coarsely chopped
1fresh or dried avocado leaf
a 10-inch cast-iron skillet; an electric coffee/spice grinder
warm corn tortillas
COOK CHICKEN AND MAKE STOCK:
Stick 2 onion quarters with a clove. Bring water, onions, celery, carrots, garlic, bay leaves, chiles, peppercorns, thyme, allspice, and 2 Tbsp salt to a boil in an 8- to 10-qt stockpot. Add chicken and gently simmer, uncovered, skimming foam, until juices run clear when pierced with a fork, 30 to 40 minutes. Transfer chicken pieces to a bowl, discarding necks and backs. Strain stock through a colander into another pot, discarding solids. Cover chicken with some of stock. Cool, then chill until ready to use.
MAKE CHILE PURÉE:
Slit chiles lengthwise, then stem and seed, reserving seeds. Heat skillet over medium heat until hot, then toast chiles in batches, opening them flat, turning and pressing with tongs, until blackened but not burned, about 10 seconds. Transfer to a large bowl and cover chiles with boiling-hot water. Weight with a plate to keep them submerged and soak 30 minutes.
Toast chile seeds in skillet over medium heat, stirring frequently, until blackened, about 20 seconds. (Be sure to toast seeds in a well ventilated area, as they give off strong fumes.) When seeds are black, light them with a match and let them burn themselves out. Transfer blackened seeds to a bowl and cover with cold water. Soak seeds 10 minutes and drain.
Working in small batches, transfer chiles to blender with tongs and purée, adding enough chile-soaking water to facilitate blending (about 1/3 cup per batch). Return 1 cup purée to blender with chile seeds and blend until smooth, about 2 minutes, adding more chile-soaking water if necessary. Force purée through a fine-mesh sieve into another bowl to remove any pieces of skin or seeds.
MAKE TOMATO PURÉE:
Cook tomatoes, tomatillos, thyme, and oregano in dry skillet over medium-high heat, turning occasionally, until charred in spots, 10 to 12 minutes. Purée mixture in cleaned blender with 1/2 cup chicken stock until smooth.
MAKING SEASONING MIXTURE:
Cook onion and garlic in dry skillet over medium heat, turning occasionally, until slightly softened and charred in spots, 8 to 10 minutes. Transfer to a bowl. Toast almonds, peanuts, cinnamon stick, peppercorns, and cloves in skillet over medium heat, stirring occasionally, until browned in spots, about 5 minutes. Add to onion and garlic.
Heat oil in skillet over medium heat until smoking, then fry raisins until plump and a shade lighter, about 1 minute. Transfer raisins with a slotted spoon to onion mixture. Fry bread in same oil, turning occasionally, until browned, about 4 minutes. Add to onion mixture. Fry plantain in same oil, adding more oil if necessary, turning occasionally, until well browned, 4 to 6 minutes. Add plantain to onion mixture.
Fry sesame seeds in oil remaining in skillet over low heat, stirring constantly and adding more oil if necessary, until they begin to brown, about 3 minutes. Add pecans and fry, stirring constantly, 2 minutes more. Transfer to another bowl, and, when cool, grind to a paste in small batches in grinder.
Purée onion mixture in 2 batches with 1 cup stock per batch in cleaned blender until very smooth, transferring to a bowl. Stir in sesame paste.
Heat lard in a 5- to 6-qt heavy pot over medium heat until melted and fat shimmers. Add chile purée all at once (it will spatter) and fry, stirring constantly and reducing heat if necessary, until purée is thickened and reduced by about one third, 15 to 20 minutes. Add tomato purée and fry over medium heat, stirring frequently, until thickened, 8 to 10 minutes.
Add seasoning mixture and simmer, stirring frequently, until mixture is well incorporated, about 10 minutes. Stir in 1 cup chicken stock and simmer, stirring occasionally, 20 minutes.
Stir in chocolate until melted. Toast avocado leaf briefly over a gas flame or in dry skillet, then add to mole. Simmer, stirring occasionally and adding more chicken stock, 1 cup at a time (2 to 4 cups total), until mole is just thick enough to coat spoon, about 30 minutes. Season with salt.
Reheat chicken in stock. To serve, ladle about 3/4 cup mole over each serving of chicken.