1 lb. fresh mushrooms (if possible, avoid the large ones)
1/2 c. grated Parmesan cheese (Kraft green cardboard can)
1/4 c. butter
1 tsp. chopped onion, rinse well

Remove stems of mushrooms.

Chop. Combine stems, cheese, butter and onion. Fill mushroom caps. Place on racks of boiler pan, broil 2 to 3 or 4 minutes until top of filling is slightly crusty. Serve hot.