Beef Medallions in Meztl Sauce

FOR MARINADE: Put all but the last marinade ingredient in a blender and blend for 2 to 3 minutes. Put the beef in a ceramic container, add the marinade, and set aside for 30 minutes.

FOR METZTL SAUCE: Heat the oil in a casserole, add the onions and garlic, and saute until transparent. Add the chiles and tomatoes, and season lightly with salt and pepper. Cook over high heat until the sauce begins to thicken. Add the cuitlacoche and mushrooms, and season again as needed. Add the epazote, cover, reduce the heat, and simmer until thickened. Adjust the seasoning to taste. Keep warm.

FOR CHEESE SAUCE: Combine all the sauce ingredients except the butter in a blender and blend until completely smooth. Heat the butter in a saucepan, and add the blended mixture to heat through, being careful not to boil. Keep warm.

TO FINISH: Heat a frying pan over high heat. When hot, add the oil and melt the butter. Brown the beef for 2 to 3 minutes on each side or longer if desired, season with salt and pepper to taste, and remove from the heat. In a separate saucepan, heat the stock and drizzle it over the beef.

TO SERVE: Serve by placing 1 piece of meat in the center of each dinner plate. Top with the metzli sauce, then spoon on the cheese sauce. Garnish with an x-cat-ik chile "flower".