Prepare the sauce. Reserve in the pan off heat. Preheat the oven to 375ºF. Place the sliced potatoes in a large bowl. Add the oil, salt, and pepper and toss to coat the potatoes. Transfer to an oven proof casserole dish and roast the potatoes, uncovered, in a preheated oven for 30 minutes. Reheat the sauce and pour over the potatoes. Cover and cook until the potatoes are very tender, about 35 to 40 minutes more. Sprinkle with the cheese and serve hot. Serves 4