Every once in a while we love to make a big turkey dinner, but we always end up with a bunch of leftovers. One great way to use up all the extra turkey is to throw it into this hearty, comforting casserole. Sort of in the same vein as a traditional gratin, the potatoes taste like hash browns after baking in the oven and the melted cheese oozes deliciously over the turkey. With just a few additional ingredients, we have a great-tasting dish. Serve this to your family and watch them scarf it down!