Spray any sized shallow baking pan (I use a 9x13 type) with cooking spray and spread leftover stuffing/dressing on the bottom. Layer with leftover turkey and top with leftover potatoes... Cover in foil which you will remove for the last 5-10 minutes.
Bake at 350 for about 45 minutes, until heated through. Let sit for a bit before cutting.. Top with leftover microwaved gravy.