Gratin Dauphinois

Name: Gratin Dauphinois
Prep time: 25 min
Cook time: 1 h 15 min
Total time: 1 h 40 min
Cuisine: France
Ingredients: 1¼ kg (2⅔ lb) floury or all-purpose potatoes (Yukon Gold, Maris Piper), peeled; 400 ml (1⅔ cups) heavy cream; 300 ml (1¼ cups) whole milk; 2 cloves garlic, finely grated, plus 1 halved clove for the dish; 2 sprigs thyme; 1 pinch freshly grated nutmeg; 12 g (2 tsp) fine sea salt; white or black pepper; 15 g (1 tbsp) unsalted butter, for the dish

Thin potatoes baked slowly in garlic-infused cream until tender and golden

Serves: 6
Hands-on: 25 min
Total: 1 h 40 min
Level: Some skill

The classic French potato gratin has no cheese — just thinly sliced potatoes, cream, milk and garlic, baked until the starch and cream turn into a silky, sliceable custard under a golden top. Simmering the slices in the cream first cuts the baking time and guarantees they cook through.

Ingredients

1¼ kgfloury or all-purpose potatoes (Yukon Gold, Maris Piper) (2⅔ lb)peeled
400 mlheavy cream (1⅔ cups)
300 mlwhole milk (1¼ cups)
2 clovesgarlicfinely grated, plus 1 halved clove for the dish
2 sprigsthyme
1 pinchfreshly grated nutmeg
12 gfine sea salt (2 tsp)
white or black pepper
15 gunsalted butter (1 tbsp)for the dish

Diet: Vegetarian, Gluten-free
Allergens: milk
Origin: France (Dauphiné)
Season: Autumn, Winter

Method

Heat the oven to 160°C (325°F). Rub a 20 × 30 cm (8 × 12 in) baking dish with the cut garlic clove, then with the butter.
Slice the potatoes 3 mm thick, by mandoline (with the guard) or a sharp knife. Don't rinse them; their starch thickens the sauce.
Put the cream, milk, grated garlic, thyme, nutmeg, salt and pepper in a large pot. Add the potatoes and bring to a gentle simmer over medium heat, stirring gently with a spatula so the slices don't stick.
Simmer, stirring gently and often, until the cream has thickened slightly and the potatoes are flexible but not cooked through, 8–10 minutes. Remove the thyme. 9 min
Tip into the dish and level the top, pressing the slices flat so the cream just covers them.
Bake until the top is deep golden in patches, the cream is bubbling at the edges and a knife slides through the center with no resistance, 60–75 minutes. 1 h 5 min
Rest 15 minutes before serving so it sets enough to cut. 15 min

Why it works

Unrinsed potato slices release starch into the cream, which thickens it into a sauce that binds the layers. Simmering first starts the starch thickening and pre-cooks the potatoes so the center is soft before the top over-browns. A moderate oven gives the cream time to reduce without splitting; cream's high fat content keeps it stable where milk alone would curdle.

Common mistakes

Slices of uneven thickness: some stay hard. Use a mandoline or take care with the knife.
Rinsing the potatoes: you wash off the starch that thickens the sauce.
Serving straight from the oven: it's runny. Let it rest.

Variations

Savoyarde-style with cheese: Scatter 100 g grated Gruyère over the top before baking.

Make ahead and storage

Bake up to 1 day ahead, cool and refrigerate. Reheat covered with foil at 170°C (340°F) for 30 minutes, uncovering for the last 10.

Notes

Fan oven: 140°C (275°F).