If you cannot find Mexican chocolate, replace with dark chocolate.
For the chile paste:
Toast the ancho chiles by opening them and pressing them flat in a hot skillet for a few seconds on each side. Soak the chiles in hot water until they are very soft, about 30 minutes. Drain and pour into a blender with the roasted poblanos and chicken broth. Pulse until pureed. Season with salt and set aside.
For the mole:
Heat the canola oil in a large skillet over medium heat. Add the almonds, hazelnuts, pecans and sesame seeds and cook, stirring until lightly toasted, about 3 minutes. Remove the nuts with a slotted spoon to a food processor or blender. Add the raisins to the same skillet and stir for a minute as they puff. Put them in with the nuts. Add the anise seeds, cumin seeds, peppercorns, cloves and cinnamon stick to the skillet and cook until fragrant, about1 minute. Transfer to the food processor. Add the garlic and onions to the skillet and cook until browned, about 10 minutes. Remove to the food processor with the nuts and raisins. Then, fry the plantains and add to the food processor with the tortillas. Add about 1 cup/250 ml chicken broth and blend to a smooth paste.
In a large skillet, heat some more oil over medium heat and pour in the mole. Add the ancho chile paste, chocolate, sugar and remaining 2 2/3 cup/660 ml chicken broth. Season with salt and pepper and continue cooking on low heat for about 1 hour. Serve the mole with roasted, grilled or poached chicken.