Potatoes au Gratin
Thinly sliced Yukon Golds baked in garlicky cream with Gruyere, white cheddar and parmesan until tender inside and bronzed and bubbling on top.
By Theo Brandt, Test Kitchen Lead & Cheese Specialist
Published May 18, 2025
- Prep
- 30 min
- Cook
- 1 hr 20 min
- Total
- 1 hr 50 min
- Servings
- 8
- Level
- Medium
Potatoes au gratin is the side dish that steals the show at every holiday table. Thin, even slices of buttery Yukon Gold potatoes are layered with a garlic and thyme infused cream and three cheeses: nutty Gruyere, sharp white cheddar and salty parmesan.
We warm the cream with the aromatics first, which seasons it thoroughly and helps the potatoes start cooking right away. Baking covered and then uncovered gives you fully tender potatoes underneath and a bronzed, crackly top.
The most important step is the rest. Give the gratin 15 to 20 minutes out of the oven so the sauce thickens and the slices hold together. Serve it with roast beef, ham or a simple green salad.
- Three-cheese creamy layers
- Bronzed crackly top
- Holiday-worthy side dish
Ingredients
Directions
Heat the oven to 375 degrees F and generously butter a 9x13-inch or similar 3-quart baking dish.
Melt the butter in a saucepan over medium heat. Add the shallot and garlic and cook until soft and fragrant, 2 to 3 minutes.
Add the cream, milk, thyme, nutmeg, salt and pepper and bring just to a simmer. Remove from the heat.
Toss the Gruyere and cheddar together, and set aside 1 cup of the mixture for the top.
Arrange one third of the potato slices in overlapping rows in the baking dish. Sprinkle with half of the remaining cheese mixture and pour about 1 cup of the hot cream over the top.
Repeat with another third of the potatoes, the rest of the cheese mixture and another cup of cream.
Layer the remaining potatoes on top and pour over the remaining cream. Press down gently so the potatoes are mostly submerged.
Cover tightly with foil and bake for 40 minutes.
Uncover, sprinkle with the reserved cheese mixture and the parmesan, and continue baking until the potatoes are completely tender when pierced with a knife and the top is deep golden brown, 35 to 40 minutes more.
Let rest 15 to 20 minutes before serving so the sauce can set. Sprinkle with chives.
Test-kitchen tips
- Bake the gratin completely a day ahead, cool and refrigerate. Reheat covered at 350 degrees F for 30 minutes, then uncover for 10 minutes to recrisp.
- Use a mandoline for even 1/8-inch slices so every layer cooks at the same rate. Do not rinse the slices; their starch helps thicken the sauce.
- Try Comte or fontina in place of the Gruyere, or tuck thinly sliced leeks or caramelized onions between the layers.
