My friend Arturo, a local caterer specializing in Mexican cuisine, prepared this for me and other friends recently. It was so delicioso I begged him for the recipe, which is as follows. Add the mushrooms, onions, garlic and sauté for several minutes, stirring constantly, until the mushrooms get browned and the onions translucent. Add a cup of wine. Reduce the wine, adding more wine as needed if the mushrooms absorb too much.
