Step 1Prepare the pasilla chiles: Place the chiles in a medium bowl. Bring a small saucepan of water to a boil, then remove from heat and pour the water over the chiles. Place a plate over the chiles to submerge them, and set aside for about 10 minutes to give the chiles time to soften. Drain the chiles, then stem and seed them. Slice the chiles crosswise into thin rounds and set aside.
Step 2Heat a large frying pan over medium-high heat until hot. Add the oil, then the onion, garlic and pasilla rounds. Cook, stirring frequently, until the onions are softened, about 5 minutes.
Step 3Stir in the mushrooms and cook, stirring frequently, until the mushrooms are tender, about 6 minutes. Off-heat, stir in the epazote and wine, then continue to cook, scraping the flavoring from the base of the pan, until the wine has mostly evaporated, about 2 minutes. Remove from heat and serve immediately.