Gratin Dauphinois

Peel the potatoes. Using a mandoline set to 2–3mm, slice each potato into uniform thin rounds. Do not rinse the sliced potato — the surface starch is what causes the cream to thicken and bind the gratin as it bakes. Place slices in a bowl as you work. The mandoline setting is not a suggestion: 4mm slices will still be firm in the center when the top is golden; 1mm slices will dissolve entirely.

In a wide saucepan, combine the cream, milk, minced garlic, salt, pepper, and a generous grating of nutmeg. Bring to a bare simmer over medium-low heat, stirring to dissolve the salt. Taste the cream — it should taste slightly overseasoned because the potato will absorb salt significantly. Do not boil. Remove from heat and set aside.

Preheat oven to 160°C (320°F). Rub a baking dish generously with the halved garlic clove, then butter it liberally. Layer potato slices evenly across the bottom, overlapping like scales. Season the layer lightly. Continue layering and seasoning until all the potato is used. Pour the hot cream mixture over the top — it should come about two-thirds up the depth of the potato. Dot with butter.

Bake at 160°C (320°F) for 60–75 minutes. For the first 45 minutes, do not open the oven — the potato is slowly absorbing the cream and the starch is thickening the matrix. At 45 minutes, increase heat to 190°C (375°F) and bake another 15–20 minutes until the top is deeply golden-brown and bubbling at the edges. Test doneness by inserting a thin knife into the center — it should slide through with zero resistance.

Allow the gratin to rest at room temperature for 15–20 minutes before serving. This rest period allows the cream matrix to firm up enough to slice cleanly. Serve in portions using a wide spatula, lifting from the bottom. The gratin reheats beautifully the next day — covered with foil at 160°C for 20 minutes.