If you enjoy scalloped potatoes but want a rich cheesy topping, make au gratin potatoes. Layers of thinly sliced potatoes cooked in a baking dish or slow cooker with heavy cream or a rich cheese sauce over them, sprinkled with cheese until the potatoes are tender and the topping is bubbly. For a sophisticated flavor, you can also sauté sliced fennel with onion to layer in between the potatoes. Top the gratin with Gruyère cheese and cook it until the cheese is browned. The instructions tell you exactly how to make this delicious side dish or light meal.