Heat the oil in a saucepan over medium heat. Add the mushrooms and salt. Cover the pan and cook until the mushrooms are just tender, about 10 minutes. Drain the mushrooms, reserving the liquid, and set both aside.
Remove the stems, slit the chiles open, and remove the seeds and veins. Cover with hot water and soak for 15 minutes, or until soft. Drain. On a hot comal, toast the chiles, making sure they do not burn.
Crush the clove, peppercorns and cumin seed with a mortar and pestle or in a spice or coffee grinder. In a blender, place the chiles, crushed spices, and garlic. Blend until smooth, adding a little water only if necessary.
In a large heavy skillet, heat the lard until smoking, then add the chile sauce and fry over a fairly high heat. Scraping the bottom of the pan often so it doesnt stick, cook until reduced, about 5 minutes.
Add sufficient water to the reserved liquid from the mushrooms to make 3/4 cup. Add this, the epazote, and mushrooms to the chili sauce, and cook over a medium heat for about 5 minutes.
Serve with rice and warm flour tortillas.
c.1996, M.S. Milliken & S. Feniger, all rights reserved