Preheat oven to 350 degrees F. In a medium saucepan, cook celery in hot butter over medium heat until tender. Stir in soup, 1/2 cup of the bread crumbs, the mushrooms, milk, and sherry. Bring just to boiling, stirring constantly. Stir in crabmeat. Transfer mixture to an ungreased 9-inch pie plate.
In a small bowl, combine the remaining 1/4 cup bread crumbs and cheese. Sprinkle over crab mixture.
Bake, uncovered, about 25 minutes or until mixture is heated through and top is golden. If desired, serve with lemon wedges. Makes 4 servings.