Cook bacon until crisp. Drain on paper towel. Crumble and set aside.
Preheat oven to 400° F. Remove mushroom stems. Set aside caps. Finely chop stems. In a sauce pan over medium heat, melt the butter. Cook and stir the chopped stems and onion until tender, about 5 minutes. Remove from heat.
In a medium bowl, stir together the mushroom/onion mixture with bacon and 1/2 cup of cheese. Mix well. Spoon into mushroom caps. Bake at 400° F for 15 minutes. Remove from oven. Top mushrooms with remaining cheese and sprinkle with parsley.
Total Fat 28g
Saturated Fat 11g
Total Carbohydrate 2g