Spread half of the stuffing in an even layer in bottom of prepared baking dish. Spread half of the cranberry sauce in an even layer over stuffing. Layer half of turkey slices on top of cranberry sauce, then spread half of the mashed potatoes on top of turkey slices. Sprinkle half of the shredded cheese on top of potatoes. Repeat layers once. Bake in preheated oven until lasagna is warmed through, about 20 minutes. Increase heat to broil, and broil until cheese is golden, about 2 minutes.