Preheat oven to 400 degrees. Remove stems from mushroom caps. Finely chop stems and set aside. In a medium pan, melt butter over medium heat. Use up to half of this butter to brush tops of mushroom caps before placing them top-side-down in a shallow baking pan. Return pan with butter to heat and add onion, garlic, and chopped mushroom stems. Saute for 3 to 4 min., or until tender and fragrant. Remove pan from heat and stir in cream cheese. Add Parmesan cheese, Parsley, Poultry Seasoning, and bread crumbs. Scoop 1 to 2 Tbsp. of stuffing mixture onto each mushroom cap. Bake for 10 to 12 min., or until heated through and tops are just beginning to brown.