2 lbs. fresh mushrooms, about 24 lg.
4 strips bacon
6 tbsp. butter
2 tbsp. minced onion
2 eggs
1 c. heavy cream
1/2 c. shredded Swiss cheese
1/2 tsp. salt

Rinse, pat dry and remove stems from mushrooms. Chop stems (makes about 1 1/2 cups). Set aside. In a large skillet, saute bacon until crisp; drain on paper towel; crumble and set aside. Pour bacon fat from skillet. In same skillet, melt butter. Use about 4 tablespoons of the butter to brush the outside of the mushroom caps; place caps in a large, shallow baking pan. To remaining butter in skillet, add onion; saute 2 minutes. Add reserved mushroom stems; saute 2 minutes longer. Remove from heat. In a bowl lightly beat eggs; stir in cheese, cream and salt. Stir in reserved bacon and the mushroom mixture. Spoon enough filling into each mushroom cap to come to the top. Bake in a preheated moderate oven at 350 degrees for 309 minutes or until filling is set. The only trick to these is to make sure the onion and mushrooms are minced exceptionally small and to use the fancy shredded Swiss cheese.