1. Heat a dry skillet over a medium heat. Add the guajillo and toast it for 30 seconds on each side. Use a spatula to press it flat on the skillet to maximize the area that gets toasted. Remove the stem. Grind it into powder and set aside.
2. Heat the oil in a large skillet over high heat. Stir in the oyster mushrooms only, then let them cook for 1 to 2 minutes until they begin to brown. Stir again, and let them sit again. Continue to do this until they are greatly reduced in size and are well browned and crispy. This will take 10 to 12 minutes. Turn the heat down to medium. Add the shiitakes and cremini mushrooms. Sauté until soft. Add the garlic, epazote (if using), reserved guajillo powder and salt and sauté another 2 minutes. Remove the pan from the heat.
3. In a blender or food processor, purée the roasted habanero (if using) with the crema and transfer to a bowl. Warm the tortillas. Fill each taco with the mushrooms, then top with the prepared crema or avocado and finish them off with a sprinkle of vegan queso fresco or pine nuts.
From Vegan Tacos by Jason Wyrick, (Vegan Heritage Press, 2014). Used with permission from the publisher.