2 head cauliflower, clean, remove leaves

Boil in large pot 25 minutes after water begins to boil. Put in roasting pan. Melt 2 sticks butter. Cook 2 onions and mushrooms if desired. Pour over cauliflower and sprinkle generously with Parmesan and shredded Cheddar cheese. Bake at 350 degrees for 25 to 30 minutes.