Mushroom Quesabirria Tacos

Cut the whole onion in half. Thinly slice one half and cut the remaining half into two pieces. Set sliced onion aside.

Prepare the consomé: Heat a Dutch oven or heavy pot over medium. When hot, add the chiles, peppercorns, allspice, cinnamon and cumin and stir gently until fragrant and cumin begins to pop, about 1 minute. Remove the spices and chiles and set aside.

Add 2 tablespoons oil to the pot, then add the onion pieces, tomatoes, garlic, oregano and 1 1/2 teaspoons salt. Stir to coat the vegetables with oil and cook for 5 minutes, until beginning to soften, then add the stock and toasted spices. Bring to a boil. Reduce to a simmer and cook until onions and tomatoes are soft, about 15 minutes. Allow to cool for a few minutes before transferring to the jar of a blender. Blend on high until smooth.

Heat 2 tablespoons oil in the Dutch oven over medium. Once the oil is hot, carefully strain the blended mixture back into the pot (some splattering might occur), pressing against the strainer with a spatula to extract as much liquid as possible. Reduce heat to low, stirring occasionally, and keep warm.

While the consomé is simmering, heat 2 tablespoons oil in a large cast-iron skillet or non-stick pan over medium-high. Working in batches to avoid crowding, add some of the sliced onions and mushrooms in a single layer. Cook until well browned and most of the moisture has evaporated, about 7 minutes. Transfer to the simmering consomé and repeat with remaining onions and mushrooms, adding more oil if needed between batches, until all are browned and in the broth. (The consomé can be made ahead and refrigerated for up to 3 days. Reheat before proceeding with the next step.)

Heat oven to 250 degrees. Wipe out the skillet and heat over medium. Place a tortilla in the pan and immediately sprinkle about 2 generous tablespoons of cheese evenly over the top. When the cheese begins to melt, about 30 seconds, use a slotted spoon to add about 1/4 cup of mushrooms and onions from the consomé to one side of the tortilla. Fold the tortilla in half over the filling. Some cheese may ooze out and caramelize; this is good. Cook for 1 to 2 minutes more, flipping once, until both sides are golden brown and crispy. Transfer to an oven-safe plate or baking sheet, along with any crispy bits from the pan, and keep warm in the oven while you make the remaining tacos.

Divide hot consomé among bowls for dipping and sipping, and serve tacos alongside with lime wedges, salsa macha, minced onions and cilantro.