Classic Potatoes au Gratin with Gruyère and Garlic

Name: Classic Potatoes au Gratin with Gruyère and Garlic
Prep time: 30 min
Cook time: 1 h 15 min
Total time: 1 h 45 min
Yield: 8 servings
Cuisine: French
Ingredients: 1 tbsp (14 g) unsalted butter, softened, for greasing the dish; 2 tbsp (28 g) unsalted butter, cut into small pieces, for the cream mixture; 1 clove (5 g) garlic, peeled and halved, for rubbing the dish; 4 cloves (20 g) garlic, finely minced; 3 lb (1360 g) Yukon Gold potatoes, peeled and sliced 1/8 inch (3 mm) thick; 2 cups (480 ml) heavy cream, cold; 1 cup (240 ml) whole milk, cold; 2 tsp (8 g) kosher salt; ½ tsp (1 g) black pepper, freshly ground; ¼ tsp (½ g) nutmeg, freshly grated; 1 tsp (2 g) fresh thyme leaves, stripped from stems (optional); 3 cups (300 g) Gruyère cheese, coarsely grated (about 10 oz / 300 g), divided

From the MyKitchenBank Kitchen

Thinly sliced potatoes are simmered briefly in garlicky cream, layered with nutty Gruyère, and baked until tender inside with a bubbling, deeply golden crust. Rich, silky, and made for roasts, ham, or holiday tables.

Prep: 30 min
Cook: 1 hr 15 min
Wait: 20 min
Total: 2 hr 5 min
Makes: 1 gratin in a 9×13-inch dish (8 servings)

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Ingredients

8 servings

1 tbsp (14 g) unsalted butter, softened, for greasing the dish
2 tbsp (28 g) unsalted butter, cut into small pieces, for the cream mixture
1 clove (5 g) garlic, peeled and halved, for rubbing the dish
4 cloves (20 g) garlic, finely minced
3 lb (1360 g) Yukon Gold potatoes, peeled and sliced 1/8 inch (3 mm) thick
2 cups (480 ml) heavy cream, cold
1 cup (240 ml) whole milk, cold
2 tsp (8 g) kosher salt
½ tsp (1 g) black pepper, freshly ground
¼ tsp (0.5 g) nutmeg, freshly grated
1 tsp (2 g) fresh thyme leaves, stripped from stems (optional)
3 cups (300 g) Gruyère cheese, coarsely grated (about 10 oz / 300 g), divided

Equipment (7)

9×13-inch (23×33 cm) baking dish, about 3 quarts
Large heavy-bottomed pot or Dutch oven (5-quart)
Mandoline or sharp chef's knife
Box grater
Aluminum foil
Rimmed baking sheet
Instant-read thermometer (optional)

Steps

Before you start

Position an oven rack in the center and preheat the oven to 375°F (190°C).
Grate the Gruyère yourself from a block; pre-shredded cheese contains anti-caking starch and melts less smoothly.
Slice the potatoes just before using and do not rinse them. The surface starch helps thicken the cream.
Place a rimmed baking sheet on the rack below the gratin to catch any bubbling overflow.

1
Prepare the dishOven 375°F / 190°C
- Preheat the oven to 375°F (190°C) with a rack in the center and a rimmed baking sheet on the rack below.
- Rub the cut sides of the halved garlic clove all over the bottom and sides of the 9×13-inch dish, then smear the softened butter over the same surfaces.
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Ready when: Dish is evenly coated with a thin, glossy layer of butter.
Tip: Rubbing the dish gives a gentle garlic aroma without any raw bite.
2
Slice the potatoes
- Peel the potatoes and slice them 1/8 inch (3 mm) thick, using a mandoline if you have one.
- Keep the slices in a large bowl and do not rinse or soak them.
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Ready when: Slices are uniform and bend slightly without breaking.
Tip: Uneven slices cook unevenly. Thicker than 1/4 inch (6 mm) risks hard centers.
3
Grate the cheese
- Coarsely grate the Gruyère on a box grater.
- You should have about 3 packed cups (300 g).
- Set aside 1 cup (100 g) for the top.
4
Simmer potatoes in cream
- In a large heavy pot, combine the cream, milk, minced garlic, butter pieces, salt, pepper, nutmeg, and thyme if using.
- Add the potato slices and bring to a gentle simmer over medium heat, stirring carefully every minute or so with a flat spatula.
- Simmer 8 to 10 minutes.
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Ready when: The liquid has thickened slightly and coats a spoon, and a potato slice is just barely tender at the edge when pierced with a knife.
Tip: Keep it at a gentle simmer, not a boil, and stir gently so slices don't break. Scorching on the bottom ruins the flavor, so scrape the bottom as you stir.
5
Layer with cheese
- Remove the pot from the heat.
- Using a slotted spoon or tongs, spread half of the potatoes in an even layer in the prepared dish.
- Sprinkle with 1 cup (100 g) of the cheese.
- Add the remaining potatoes and spread level.
- Pour the remaining cream mixture over the top; it should come about three-quarters of the way up the potatoes.
- Press down gently with a spatula.
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Ready when: Potatoes are level and the cream is visible around and between the slices.
Tip: Taste the cream before pouring; it should taste slightly salty, as the potatoes will absorb seasoning.
6
Bake coveredOven 375°F / 190°C
- Cover the dish tightly with foil.
- Bake at 375°F (190°C) for 30 minutes.
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Ready when: Cream is bubbling at the edges when you lift a corner of the foil.
Tip: Tent the foil so it doesn't touch the surface and stick to the potatoes.
7
Add cheese and brownOven 375°F / 190°C
- Remove the foil and sprinkle the reserved 1 cup (100 g) Gruyère evenly over the top.
- Bake uncovered at 375°F (190°C) for 30 to 35 minutes more.
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Ready when: The top is deep golden brown with bubbling edges, and a paring knife slides into the center with no resistance (about 195°F / 90°C inside).
Tip: If the top browns too fast, loosely cover with foil for the last 10 minutes. For extra color, broil 1 to 2 minutes, watching constantly.
8
Rest before serving
- Remove the gratin from the oven and let it rest on a rack for 20 minutes.
- Cut into squares and serve warm.
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Ready when: The bubbling has stopped and the sauce has thickened enough to hold a clean cut.
Tip: Skipping the rest gives a runny gratin that slides apart.

Good to know

Tips

Uniform slices are the key to even cooking; a mandoline is worth using.
Do not rinse the potatoes. Their surface starch thickens the cream into a silky sauce.
Pre-simmering the potatoes in the cream shortens the bake and prevents curdling or raw centers.
Place a baking sheet underneath to catch drips and keep your oven clean.

Make ahead

"Assemble the gratin through step 5, cool, cover, and refrigerate up to 24 hours. Bake covered for 40 minutes, then uncovered 30 to 35 minutes, until bubbling and tender. Alternatively, bake fully, cool, and refrigerate, then reheat as directed under storage."

Storage & reheating

"Room temperature: up to 2 hours after baking. Refrigerator: covered, up to 4 days. Freezer: not recommended, as the cream sauce can separate and the potatoes turn grainy. To reheat, cover with foil and warm at 350°F (175°C) for 20 to 25 minutes, then uncover for 5 minutes to re-crisp the top."

Substitutions

Gruyère cheese → Comté, Emmental, or a mix of Swiss and sharp white cheddar. Melts similarly; cheddar gives a sharper flavor.
Yukon Gold potatoes → Russet potatoes. Fluffier and more absorbent, but they break more easily, so stir very gently.
whole milk → Additional heavy cream (1 cup / 240 ml). Makes it richer; reduce the bake uncovered by about 5 minutes if it looks very bubbly.
fresh thyme leaves → Fresh rosemary, very finely minced (1/2 tsp). Stronger flavor, so use less.