To begin, preheat your oven to 160°C (320°F). Prepare a large bowl for combining your ingredients. Thinly slice the potatoes using a mandolin or sharp knife for uniform slices, about 3-4 mm thick. This ensures even cooking and a creamy texture

In a small saucepan over low heat, gently warm the cream and milk together. Stir in the minced garlic, a pinch of nutmeg, and season generously with salt and pepper. This infused mixture will coat the potatoes beautifully. Do not let it boil, just warm through.

Grease a medium sized baking dish with butter, ensuring even coverage on the base and sides. Layer half of the sliced potatoes in the dish, arranging them evenly to create a uniform layer.

Pour half of the warm cream mixture over the potatoes, ensuring every slice is covered. You can gently tilt the dish to distribute the liquid if necessary. Add the second layer of potato slices on top, creating a neat finish.

Pour the remaining cream mixture over the second layer of potatoes, ensuring they are all well coated. Gently press down the potatoes to submerge them slightly into the cream mixture. This step helps ensure the gratin cooks evenly and absorbs all the flavors.

For added richness, sprinkle the grated Gruyère cheese over the top of the potatoes (optional). The cheese will form a golden, bubbling crust, adding depth to the dish. However, traditional Gratin Dauphinois is often made without cheese, relying on the creamy potatoes alone.

Cover the dish loosely with foil and place it in the preheated oven. Bake for 1 hour, allowing the potatoes to cook through and soften. After 1 hour, remove the foil, increase the oven temperature to 180°C (350°F), and bake for an additional 20-30 minutes until the top is golden brown and bubbling.

Remove the gratin from the oven and let it rest for 5-10 minutes before serving. This resting period allows the flavors to settle and makes slicing easier. Serve warm, garnished with fresh thyme or parsley, alongside roasted meats or a green salad.