* Garlic cloves should be peeled and split. ** Potatoes should be peeled and sliced paper-thin. (Slice at the last minute so that they do not darken; do not soak in cold water).
Preheat the oven to 325 degrees F. Rub the bottom and sides of a gratin dish with the cut sides of the garlic. Leave the garlic in the dish. Cover with a layer of potatoes. Sprinkle with some salt and freshly ground pepper and cheese. Pour some cream over the whole thing. Repeat until all the potatoes, cream, and cheese are used. Place the pan, uncovered in the oven. (Put a baking sheet underneath to catch spills. ) Bake for 1 hour or more, until the top is browned and the cream has cooked down to a thick sauce. During the first 1/2 hour of cooking, use a broad spatula to push the top layers of potatoes into the cream every once in a while. Serve hot, at room temperature or cold.