Preheat an oven or a gas grill to 350 to 375 degrees F.
Clean the contents from the turkey cavity, rinse, and pat dry. Season turkey with salt and pepper, to taste (be generous.) Fill cavity of turkey with bell pepper, onion, celery stalks, apple and margarine. Place in a baking bag and seal. Place in an aluminum-baking pan, breast side down. Put in oven or outdoor gas grill and cook for 2 1/2 to 3 hours.