Preheat oven to 400F.  Clean mushrooms by wiping with a paper towel and using a spoon to remove black gills.  Lay on a baking sheet and cook for about 10 minutes.  Remove from oven and drain any of the water that accumulates, pat dry with towel.  Put back on tray, top with tomato sauce and cheese and if desired any toppings.

Switch the oven to the broil setting and cook mushroom a few minutes until cheese melts.