Preheat oven to 400 F degrees.

In a medium bowl add the Parmesan cheese, bacon, parsley and salt and pepper to taste. I usually don't add any salt because I find the Parmesan cheese and bacon provides enough saltiness, but I do add about 1/2 tsp of black pepper. Stir everything together and set aside.

In a large oven safe skillet, add the olive oil and heat it over medium heat. Add the mushrooms and cook on both sides for about 2 or 3 minutes per side, just until the mushrooms start to brown a bit.

Add about 1 tbsp of the bacon/cheese mixture to each mushroom, you should have enough to fill all the mushrooms.

Place the mushrooms in the oven and bake for 5 minutes or until the cheese has melted.