Dauphinoise Potatoes (Creamy Garlic Potato Gratin)

Preheat the oven to 170 degrees Celsius.

Spread the 20 g butter evenly over the inside of the baking dish, reaching the corners so the potatoes do not stick or dry out at the edges.

Trim the 800 g potatoes, then slice them evenly to 2 mm thickness.

Rinse the slices in water, separate any pieces that cling together, and pat them very dry with paper towels, including between stacked slices.

Combine 350 ml heavy cream, 120 ml milk, 2 minced garlic cloves, and 1 teaspoon salt in a saucepan.

Warm over low heat only until light steam rises, stirring so the dairy does not catch on the bottom.

Lay the potato slices in the dish with slight overlaps, then spoon on a thin layer of the warm cream mixture.

Repeat the layering, pressing gently so the potatoes are evenly moistened without large dry gaps.

Scatter the 80 g gruyere evenly over the top and bake for 55 to 60 minutes.

If the surface browns before the potatoes are tender, cover it loosely with foil and continue baking until a knife slides in easily.

Remove the gratin when the center offers little resistance and the cream bubbles at the edges.

Let it rest for 10 minutes before cutting, so the layers settle and each portion lifts out cleanly.