Rinse oysters; pat dry with paper towels. In a large skillet cook and stir oysters in 1 tablespoon of the butter or margarine for 3 to 4 minutes or until oyster edges curl; drain. Divide oysters among four 8- to 10-ounce casseroles or four 10-ounce custard cups.
For sauce, in the same skillet cook mushrooms and garlic in remaining 2 tablespoons butter or margarine until tender. Stir in flour. Add milk all at once. Cook and stir until thickened and bubbly. Stir in wine, parsley, and Worcestershire sauce. Spoon over oysters. In a small bowl toss together the bread crumbs, Parmesan cheese, and the 1 tablespoon melted butter or margarine. Sprinkle over casseroles. Bake in a 400 degree F oven about 10 minutes or until crumbs are brown. Makes 4 servings.