6clovesgarlic, peeled, plus 2 tablespoons finely chopped garlic
3/4cupfinely chopped white onion
2dried guajillo chiles, stemmed, seeded and finely chopped or snipped with scissors
1lbmixed mushrooms, such as white button, baby bella, and wild mushrooms, thinly sliced
3/4tspkosher salt, or more to taste
1/4tspfreshly ground black pepper, or to taste
4cupsgrated mixed melting cheeses, such as asadero, Oaxaca, Monterey Jack, or mozzarella
8 to 10flour and/or corn tortillas
Guacamole or 1 ripe avocado, halved, pitted, and sliced (optional)
Salsa, of your choice for serving (optional)
To Prepare
Preheat the oven to 450 degrees F, with a rack in the upper third. Lightly oil a large shallow baking dish.
Heat the oil in a medium saucepan over medium heat. Add the whole garlic cloves and cook, stirring occasionally, until they soften and brown, 7 to 8 minutes. Remove with a slotted spoon and discard, leaving the flavored oil behind.
Add the onion and guajillo chiles and cook, stirring, for 1 to 2 minutes, just until the onion begins to soften. Add the chopped garlic, stir, and cook for a minute, until fragrant. Stir in the mushrooms, salt, and black pepper and cook, stirring occasionally, until all the mushroom juices have been released and begun to evaporate and the mushrooms have begun to color, 8 to 10 minutes. Remove from the heat, taste, and adjust the salt.
Combine the cheeses thoroughly and arrange in the baking dish. Bake for 12 to 15 minutes, or until the cheese is completely melted. Top with the mushrooms, return to the oven, and bake for another 7 to 8 minutes, until the cheese is bubbling, the edges are crusty, and the top is lightly browned.
Meanwhile, heat a comal or large skillet over medium-low heat for at least 5 minutes. One or two at a time, depending on the size of your comal or pan, heat the tortillas, making sure they are not overlapping, until warm, puffed, and browned in spots, about a minute per side. Place in a tortilla warmer or wrap in a clean cloth or kitchen towel.
Serve the queso bubbling hot from the oven, with the warm tortillas and guacamole or avocado slices and salsa, if desired. Let everyone assemble their own tacos at the table.