Preheat oven to 350°.
Heat the oil and sauté the onion with a teaspoon of brown sugar for 8-10 minutes.
Grease a 2 quart casserole dish and arrange the potatoes on the bottom. Make a layer of onions over the potatoes followed by the port chops.
Stir the dry mustard into the sherry and pour over the pork chops. Cover the dish and bake 45 minutes, or until the potatoes are tender.
Heat the butter in a skillet and sauté the apples slices for 3-4 minutes. Blend the remaining tablespoon brown sugar, cinnamon and cloves together and sprinkle over the apples. Spread the apples over the chops and serve immediately.