Cut tomatoes in half; scoop out and discard pulp, leaving a thin shell. Sprinkle lightly with salt; invert on paper towels to drain for 15 minutes.
In a large skillet, sauté mushrooms in butter until most of liquid has evaporated, about 5 minutes. Sprinkle with flour; stir in cream. Bring to boil; cook and stir for 2 minutes or until thickened.
Remove from the heat. Stir in the bread crumbs, parsley and 1/3 cup of cheese. Spoon into tomato cups; sprinkle with remaining cheese. Place in a greased 13-by-9-by-2-inch baking dish. Bake, uncovered, at 400 degrees for 10 minutes or until cheese is melted.