In a large bowl, combine the turkey, ham and cheese; set aside. In a saucepan, sauté the chopped onion and celery in butter until tender. Add flour; stir to form a paste. Gradually add the cream, stirring constantly. Bring to a boil; boil one minute or until thick. Add dill, mustard, and nutmeg; mix well. Remove from the heat and pour over the meat mixture. Spoon into a greased 9x13x2-inch baking dish.
For the topping: Toss the bread crumbs, butter and lemon pepper together. Stir in the cheese and nuts. Sprinkle over the casserole and bake, uncovered in a 350° oven for 35-40 minutes.
Recipe provided by Ohio Poultry Association.