Wash the mushrooms and remove the stems. Chop mushroom stems finely and set aside.

Brown and drain the sausage and set it aside.

Add onions, garlic and chopped mushroom stems to the same skillet.  Cook over medium heat until onions are soft.  In a bowl, combine cream cheese, sauteed mushrooms, onions, garlic, and parmesan cheese.

Fill mushroom caps with the sausage/ cheese mixture.  Make sure you heap it on top.

Bake at 350 degrees for 20 to 25 minutes, or until golden brown.