Peel the potatoes and slice them thinly (about 1/8 inch or 2-3 mm thick). A mandoline is ideal for getting even slices. Mince the garlic. In a saucepan, combine the cream, milk, and garlic. Season with salt, pepper, and a pinch of nutmeg. Gently warm the mixture over low heat, but do not let it boil. Grease a large, shallow baking dish with butter. Begin layering the potato slices evenly in the dish. After each layer of potatoes, pour a bit of the cream mixture over the top. Continue layering until all potatoes are used. Dot the top with small pieces of butter. Preheat the oven to 320°F (160°C). Bake the gratin for about 1 1/2 hours, or until the potatoes are tender and the top is golden brown. Let the gratin rest for a few minutes before serving to allow it to set. Serve as a side dish or on its own with a fresh salad.

This dish is perfect for pairing with roast meats or as a comforting standalone dish. It’s rich, creamy, and filled with the flavors of the Rhône region!