Adjust oven rack to upper-middle position and preheat broiler to high (525°F). Line a sheet pan with foil and arrange the tomatillos, tomatoes, onion, plantain, and garlic cut-side down. Broil until charred and blistered on one side, 4–8 minutes. Transfer to a blender, add 1 cup of chicken broth, and blend starting on low, working up to high until completely smooth and cohesive, about 1 minute. Pour into a large stockpot or Dutch oven.

On the same foil-lined sheet pan, spread all your chiles. Open a window. Have your partner stand nearby — ideally with a fire extinguisher, just in case. Broil until the chiles are darkened and smoking. Transfer to the blender (don't breathe in). Blend low to high, adding broth only as needed to thin the mixture. Scrape down the sides and add to the Dutch oven with the pureed vegetables. You may now remove your gas mask.

In a separate pot or skillet, add the vegetable oil and heat over medium-high until shimmering, about 340°F if you’re temping it. Add the almonds, peanuts, and pepitas and fry until the nuts smell nutty and aromatic, about 3 minutes. Using a non-metal slotted spoon, transfer the solids to the blender. Leave the oil in the skillet — you’ll need it for the next step.

In the remaining oil, add the tortillas and bread. Fry over medium-high heat, flipping, until golden-brown, about 2 minutes. Add the prunes and cinnamon stick and keep frying until everything darkens further, another 2–3 minutes. Use a wooden or non-metal slotted spoon to transfer all the solids to the blender. Leave the oil behind.

Pour all but a few tablespoons of the oil into the pot with the pureed veggies and chiles. To the skillet with the remaining oil, add the cloves, anise, allspice, a few black peppercorns, cumin, thyme, and oregano. Fry over medium-high heat until fragrant, about 1 minute. Let cool slightly, then transfer the spices and oil to the blender with the nuts and bread mixture. Blend on high until completely smooth. Transfer to the pot with the other pureed ingredients.

Add 4 cups of chicken broth to the pot and stir to combine until smooth. Bring to a boil, then reduce heat to low and gently simmer 1–1½ hours until the flavors meld and the mole — “sauce” in Nahuatl — thickens further. Add the chocolate and stir until melted. The mole is ready when it coats the back of a spoon. For a silkier finish, let it cool and run it through the blender once more.

Taste and adjust with salt and a pinch of sugar. A small splash of the reserved chile soaking liquid can add more depth — add cautiously, as it can turn bitter. The mole will be better the next day. Store in the fridge up to 1 week, or freeze for 3 months.