Preheat the oven to 350ºF.
In a large bowl, beat the cream cheese until smooth.
Stir in the parmesan cheese, green onions, parsley, old bay, and black pepper. Gently mix in the crab. Taste, and add salt if needed.
Fill each of the mushroom caps with some of the filling. Place in a baking dish.
Sprinkle the tops with more parmesan cheese.
Bake until the mushrooms are soft and the filling is heated through, about 20-40 minutes, depending on the size of the mushrooms*.
Serve hot.
