A classic French gratin of thinly sliced potatoes baked in a creamy garlic-infused sauce with a golden, cheesy crust. This indulgent side dish is perfect for special occasions or a comforting dinner.
Preheat oven to 375°F (190°C). Butter a 9x13-inch baking dish.
In a medium saucepan, combine heavy cream, milk, garlic, salt, pepper, and nutmeg. Heat over medium heat until just simmering, then remove from heat.
Arrange half of the potato slices in an even layer in the prepared dish. Pour half of the cream mixture over the potatoes. Sprinkle with half of the Gruyère.
Layer remaining potatoes on top, pour remaining cream mixture, and top with remaining cheese.
Bake for 50-60 minutes, until potatoes are tender when pierced with a knife and the top is golden brown and bubbly. Let rest for 10 minutes before serving.
Tips
For even cooking, slice potatoes uniformly using a mandoline.
Let the gratin rest after baking to allow the sauce to thicken slightly.
Leftovers can be refrigerated for up to 3 days; reheat in the oven.