Potatoes au Gratin Recipe

Ingredients

2 lbs (900g) potatoes, peeled and thinly sliced
2 cups (480ml) heavy cream or crème fraîche
1/2 cup (120ml) whole milk
4 cloves garlic, minced
1 small onion, thinly sliced (optional)
1 1/2 teaspoons salt (adjust to taste)
1/4 teaspoon white pepper
1/4 teaspoon nutmeg, freshly grated (optional but recommended)
2 tablespoons butter, softened
1/2 cup (60g) Gruyère cheese, grated (or Swiss cheese)
2 tablespoons Parmesan cheese, grated
Fresh thyme for garnish (optional)

Instructions

1Prepare the Pan

Preheat your oven to 350°F (175°C). Rub the softened butter around the inside of a 9x13 inch (23x33 cm) baking dish or similar sized gratin dish. This prevents sticking and adds rich flavor. You can also use a round gratin dish if preferred.

2Make the Cream Sauce

In a saucepan, heat the heavy cream and milk together over medium heat until it just begins to steam (don't boil). Add the minced garlic and stir well. Season with salt, white pepper, and nutmeg if using. Taste and adjust seasoning as needed. Remove from heat and let it cool slightly for about 2 minutes.

3Layer the Potatoes

Arrange a layer of sliced potatoes on the bottom of the prepared dish, overlapping them slightly like tiles. If using onion, sprinkle some thin slices over the potatoes. Season lightly with salt and pepper. Pour about 1/3 of the hot cream mixture over this layer, making sure it flows between the potato slices.

4Continue Layering

Create a second layer of potatoes in the same manner, adding more onions if using. Pour another 1/3 of the cream mixture over this layer. Create a final layer with the remaining potatoes, onions, and the remaining cream mixture. The cream should come up about 3/4 of the way up the potatoes—don't submerge them completely.

5Add the Cheese Topping

Combine the grated Gruyère and Parmesan cheese in a small bowl. Sprinkle this mixture evenly over the top of the gratin. The combination of these two cheeses provides excellent flavor—Gruyère melts beautifully while Parmesan adds sharpness and helps create a golden crust.

6Bake

Bake in the preheated 350°F oven for 45-50 minutes, until the potatoes are tender when pierced with a knife and the top is golden brown and bubbly. If the top begins to brown too quickly before the potatoes are cooked through, cover loosely with aluminum foil for the final 15-20 minutes of cooking.

7Rest and Serve

Remove from the oven and let rest for 5-10 minutes before serving. This allows the dish to set slightly and makes it easier to scoop. Garnish with fresh thyme if desired. Serve hot as a side dish alongside roasted meats, chicken, or fish. The creamy, tender potatoes with their golden cheese crust are absolutely delicious.

📝 Chef's Tips for Perfect Potatoes au Gratin

Potato Selection: Use waxy potatoes like Yukon Gold or red potatoes rather than starchy russets. They hold their shape better and don't fall apart during cooking. Slice them uniformly (about 1/8 inch thick) for even cooking.
Slicing Tip: A mandoline slicer makes uniform slicing easy and quick. Just be careful with your fingers! Alternatively, use a sharp knife and slice carefully.
Cream Quality: Use full-fat heavy cream or crème fraîche for the best flavor and texture. Half-and-half can be used but the sauce may be thinner.
Garlic Infusion: Mincing the garlic fine ensures it distributes throughout the cream. Some recipes cook whole garlic cloves and remove them, but minced garlic adds more flavor.
Cheese Choices: Gruyère is traditional and melts beautifully. Swiss, Emmental, or even aged cheddar can work, but Gruyère is superior. Avoid pre-shredded cheese with anti-caking agents when possible.
Nutmeg Magic: A tiny pinch of freshly grated nutmeg (not pre-ground) elevates the entire dish. It's optional but highly recommended.
Don't Overmix: When layering, don't stir or disturb the potatoes. Keep them arranged in neat layers so they cook evenly and look beautiful.
Cream Level: The cream should come up about 3/4 way up the potatoes, not cover them completely. As the potatoes cook, they release moisture which combines with the cream.
Temperature Control: 350°F is the sweet spot. Higher temperatures brown the top too quickly. Lower temperatures take longer but ensure creamy interiors.
Make Ahead: You can assemble this dish several hours ahead, cover with plastic wrap, and refrigerate. Add 10-15 minutes to baking time if baking from cold.
Leftovers: Potatoes au gratin keep well in the refrigerator for 3-4 days. Reheat gently in a 325°F oven covered with foil to prevent drying.