12–15 mild to medium dried chiles (like New Mexico, mulatto, pasilla, guajillo, ancho, or a combination), toasted, soaked, de-seeded, and de-stemmed
2cups assorted nuts (like peanuts, almonds, pecans, walnuts, pine nuts, and hazelnuts)
1/4cup tahini or sesame seeds
1/4cup cocoa powder or chopped unsweetened chocolate
1 large onion, cut into large chunks
1 head garlic, cloves separated and peeled
4 plum tomatoes (canned are fine)
2 thick slices white bread (stale is fine)
4cups vegetable stock or water, plus more as needed
1/4cup good-quality vegetable oil, plus more for frying
3 or 4 bay leaves
1 cinnamon stick
2 tablespoons ground cumin
1 tablespoon ground allspice
2 teaspoons anise seeds
Salt and pepper
Brown sugar (optional)
24 small corn tortillas, plus more if any break
4cups cooked, mashed, and seasoned sweet potatoes
1/2cup crumbled queso fresco for garnish
1/2cup chopped red onion or scallions for garnish
1/2cup chopped fresh cilantro for garnish
Lime wedges for garnish
Instructions
Put the chiles, nuts, tahini, cocoa, onion, garlic, tomatoes, and bread in a blender with just enough stock to get the machine running, and purée. (You may have to work in 2 batches.)
Put the oil in a large, deep pot over medium heat. Add the puréed mixture, bay leaves, cinnamon, cumin, allspice, and anise seeds. Sprinkle with salt and pepper. Cook, stirring frequently and scraping the bottom of the pan, until it begins to color and become fragrant, 3 to 5 minutes. Turn the heat to low and continue cooking, stirring occasionally, until the mixture is deeply colored, softened, and nearly dry, another 15 to 20 minutes.
Turn the heat back up to medium-high and slowly stir in the remaining stock. Bring to a boil, then lower the heat so the sauce barely bubbles. Cook, stirring occasionally and adding more liquid as needed, for an hour or so, until the sauce is thick and smooth. Taste and adjust the seasoning; add a tablespoon or so brown sugar if you like. (You can make the mole in advance up to this point. Cool, cover, and refrigerate for up to 3 days. Gently reheat before proceeding.) Remove the cinnamon stick and bay leaves and keep the sauce warm.
Heat the oven to 350°F. Spoon a thin layer of the mole in a 9 × 12-inch baking dish. Put about 1/2 inch oil in a large, deep skillet over medium-high heat. When it’s hot, cook the tortillas, one at a time, until softened and pliable, about 10 seconds. Drain on paper towels. Add more oil to the pan as needed.
Spoon 2 heaping tablespoons of the mashed sweet potatoes in the center of each tortilla, roll tightly, and put into the baking dish, seam side down. The enchiladas should be in a single layer, packed in snugly against one another. Cover the top with some more mole. Bake until hot and lightly browned, 25 minutes. When you take the enchiladas out of the oven, sprinkle with the queso fresco, onion, and cilantro. Serve with lime wedges on the side and pass the remaining mole at the table.