Remove stems from mushrooms (discard or save for another use); set caps aside. In a small skillet, sauté onion in 1 tablespoon olive oil until tender. In a small bowl, combine the cream cheese, egg, bread crumbs, ½ cup grated Parmesan cheese and seafood seasoning. Gently stir in crab and onion.
Spoon ½ cup crab mixture into each mushroom cap; drizzle with remaining oil. Sprinkle with paprika and remaining Parmesan cheese. Place in a greased 15-by-10-by-1-inch baking pan.
Bake, uncovered, at 400 degrees for 15–20 minutes or until mushrooms are tender.