Combine 1/2 cup melted butter, boiling water, onion, parsley and celery with stuffing in a mixing bowl. Spoon into 6 separate mounds in a buttered 9"x13" baking dish. Place chicken breast over stuffing mix, lay ham over chicken and tuck ends under, if possible secure with toothpicks. Drizzle remaining 1/4 cup melted butter over top, cover with foil, bake 1 hour at 350 degrees or until fork tender. Remove toothpicks and serve with sauce.
SAUCE: Place 1/2 cup mayonnaise (not salad dressing), 2 tablespoons milk, 2 tablespoons sherry and 1/4 cup grated Parmesan cheese. Heat over medium heat in saucepan.
