Potato Gratin with Thyme
Sliced potatoes baked slowly in cream until the dish turns into its own sauce.
- Serves
- 6
- Prep
- 20 min
- Cook
- 1 hr 15 min
- Written
Method
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Heat the oven to 375°F and butter a 9x13-inch baking dish.
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Combine the cream, milk, garlic, and thyme in a saucepan and bring to a bare simmer, until steam rises and small bubbles ring the edge.
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Season the potatoes with salt and pepper, then shingle half of them into the dish in overlapping layers.
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Pour half the warm cream over the potatoes and scatter over half the Gruyère.
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Layer in the rest of the potatoes, pour over the remaining cream, and top with the last of the cheese and a grating of nutmeg.
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Dot with butter, cover tightly with foil, and bake until a knife slides into the center with no resistance, about 45 minutes.
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Uncover and bake until the top is deeply browned and bubbling at the edges, another 20 to 30 minutes.
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Let the gratin rest for 10 minutes before cutting, so it sets instead of running across the plate.
Notes
The potatoes give up their starch as they bake, and that’s what turns the cream into a sauce instead of a puddle under a stack of vegetables. Slice them no thicker than a coin, and don’t skip warming the cream with garlic and thyme first — it’s the only seasoning that reaches the middle layers. Russets are the right choice because they break down slightly; a waxier potato holds its shape and stays gritty in the sauce.
Serve it next to the sheet-pan chicken or the grilled skirt steak, or eat a large bowl of it on its own and call that dinner.