Wash mushrooms and pat dry. Remove stems; chop and set aside. In large skillet, fry bacon until crisp. Drain, then crumble. Pour bacon fat from skillet and br ush mushroom caps with 4 tablespoons of butter. Place in large shallow baking p an. Fry onion in remaining butter about 2 minutes. Add reserved stems and cook 2 minutes longer. Remove from heat. In a bowl, lightly beat eggs. Stir in cream , cheese and salt. Stir in crumbled bacon and the mushroom mixture. Spoon enoug h filling into each mushroom to come to the top. Bake at 180ºC or 30 min utes or until filling is set. Recipe from "One Million Recipes CD" busted by Judy R.