Scalloped Potatoes (French Gratin Dauphinois)

Gratin dauphinois is a French dish of sliced potatoes baked in milk or cream, from the Dauphiné (Rhône-Alpes), a region in south-eastern France. There are many variants of the name of the dish, including pommes de terre dauphinoise, potatoes à la dauphinoise and gratin de pommes à la dauphinoise. An authentic gratin dauphinois doesn’t have any cheese. It is just made of sliced potatoes baked in milk, or cream. The preparation is easy and the result always satisfying. And really, gratin dauphinois is all about the flavour of the potatoes, and the creaminess that binds the slices together. Some recipes call for cooking the potatoes in 100% cream, but the result is a bit over the top (oh, really?) and I find one gets excellent results using mostly milk, and just a little cream. The trick is to start by pre-cooking the potatoes on the stove, just until the milk thickens enough to coat them well, and then finish cooking and browning the gratin in the oven: this shortens the overall cooking time, and it ensures that the potatoes are cooked thoroughly, from top to bottom. A murmur of nutmeg is traditional, and with good reason. I don’t add black pepper to the dish, because I prefer to grind it fresh at the table, but if I have chives (ciboulette) on hand, I’ll snip and sprinkle some amid the potatoes.

5 cups whole milk
2.2 lbs baking potatoes, peeled and cut crosswise into ¼" slices (1 kg)
1½ tsp. sea salt
½ tsp. black pepper, freshly ground
½ tsp. nutmeg, freshly grated
1 clove garlic, sliced lengthwise
3 Tbsp. fresh chives, finely chopped, optional
1½ cups heavy cream (375 mL)
1½ cups crème fraîche (375 mL)

In a large saucepan over medium heat, bring the potatoes and milk to a gentle simmer. Continue simmering the potatoes for 15 minutes, until they just start to turn tender.

Preheat the oven to 425°F (220°C/200°C fan, Gas Mark 7). Butter a large baking dish and rub the bottom and sides of the dish with the cut side of garlic.

Drain the milk from the pan and add the heavy cream, crème fraîche, salt, pepper and nutmeg to the hot potatoes. Heat the cream-crème fraîche to just under a simmer (a few bubbles are fine) for 10-15 minutes, until the potatoes are very tender, but not falling apart.

Spread half of the potato-cream mixture into the prepared baking dish. Sprinkle with chives, if using, and drizzle with half of the cream-crème fraîche. Add the rest of the potatoes, and drizzle with the remaining cream.

Bake for 35-40 minutes, until bubbly on the edges and nicely browned at the top. Let stand for about 10 minutes before serving.

Cook's Notes: You can also bake the gratin a few hours ahead, let cool and reheat for 15 minutes in a 220°C (430°F) oven before serving.