How to Make It
In a medium bowl, cover all of the chile peppers with hot water. Let them stand for 30 minutes.
Meanwhile, in a large skillet, combine the 1/3 cup of sesame seeds with the anise, cumin, coriander, cloves, peppercorns and cinnamon stick. Toast over moderately low heat, stirring, until fragrant, about 2 minutes. Transfer to a spice grinder and let them cool completely. Grind the seeds and spices to a fine powder.
In the same skillet, melt 1 tablespoon of the lard. Stir in the raisins, almonds, pumpkin seeds and tortilla. Cook the mixture over moderately low heat until the almonds are toasted and the raisins are plump, about 5 minutes. Transfer the contents of the skillet to a large bowl.
Add the tomatoes to the skillet and cook, turning, until the skins are lightly blistered on all sides, about 12 minutes. Transfer the blistered tomatoes to the bowl. Add the garlic and onion to the skillet and cook, stirring, until lightly browned, about 8 minutes. Transfer the garlic and onions to the bowl and let cool. Empty the vegetables onto a work surface. Peel the garlic cloves and coarsely chop them along with the onions and tomatoes.
Melt 1 tablespoon of the lard in the skillet. Stir in the chopped vegetables and the spice powder and cook over moderately high heat until warmed through, about 3 minutes. Add the drained chiles and the chicken stock, cover partially and simmer for 1 hour. Remove from the heat. Working in batches, transfer the contents of the skillet along with the chocolate to a blender and puree until smooth. Season the mole sauce with salt and pepper.
Preheat the oven to 350°. Season the chicken with salt and pepper. Melt the remaining 3 tablespoons of lard in a large, ovenproof skillet. Working in 2 batches, brown the chicken over high heat, turning once, about 10 minutes per batch. Pour the mole sauce over the chicken and bring to a simmer. Cover and braise in the oven until the meat is very tender, 1 hour. Transfer the chicken mole to a serving platter, garnish with the remaining 1 tablespoon of sesame seeds and the cilantro and serve.
Chiles negros can be found from specialty-food shops such as mexgrocer.com; they can also be replaced with ancho chiles. Mexican chocolate can be found at grocery stores like Whole Foods and online at mexgrocer.com