Remove stems from mushrooms; set caps aside. Finely chop stems.
In a large skillet, saute chopped mushrooms in 1/4 cup butter for 5 minutes or just until tender. Add garlic; saute 1-2 minutes longer or until garlic is golden. Remove from the heat; stir in the crab, Romano, parsley, garlic powder and onion powder.
Melt remaining butter; pour into a 13-in. x 9-in. baking dish. Fill mushroom caps with crab mixture; place in baking dish. Sprinkle with Parmesan and garlic salt.
Bake, uncovered, at 350° for 20-25 minutes or until mushrooms are tender. Sprinkle with mozzarella. Bake 2-4 minutes longer or until cheese is melted. Serve warm.