Crispy Truffle Potato Gratin with Gruyere Cream

This truffle potato gratin layers paper-thin Yukon Gold potatoes with leeks and aged Gruyere in a bubbling garlic-thyme cream, all baked in a buttered cast iron skillet until the top is golden and the edges are crisp. The result is a rich, creamy, and deeply savory side that pulls into stretchy, cheesy wedges. A final drizzle of truffle oil adds an earthy aroma that makes this dish feel extra special, yet it comes together with simple ingredients and straightforward steps.

Potato gratin is a classic comfort dish, but this version takes it to a new level with a few thoughtful touches. Slicing the potatoes paper-thin ensures they cook through evenly and become meltingly tender. Layering them in overlapping spirals creates a beautiful presentation and helps the cream distribute evenly.

The leeks add a subtle onion sweetness, while the aged Gruyere brings nutty, salty depth. Baking in a cast iron skillet gives the gratin a crispy, golden crust that contrasts with the creamy interior. A final hit of fresh thyme and truffle oil brightens the dish and adds an elegant aroma.

Ingredients

Why this recipe works

The method of slicing potatoes paper-thin and layering them in overlapping spirals is what makes this gratin so successful. Thin slices cook quickly and evenly, so the potatoes become tender without turning to mush.

The overlapping pattern creates many small pockets where the cream can pool, ensuring every bite is moist and flavorful. The cast iron skillet also plays a key role: it heats evenly and holds heat well, which helps the bottom and edges develop a crispy, caramelized crust while the center stays creamy.

The garlic thyme cream is another essential component. Simmering the cream with garlic and thyme before pouring it over the potatoes infuses the entire dish with flavor from the inside out. The cream reduces slightly during baking, concentrating its richness and clinging to the potato layers.

The aged Gruyere, melted on top, forms a golden, bubbling crust that stretches beautifully when you lift a wedge. Each element works together to create a gratin that is both elegant and deeply satisfying.

Notes and substitutions

Yukon Gold potatoes are the best choice here because they have a buttery flavor and a medium starch content that holds up well to baking. They become creamy and tender without falling apart. If you prefer, you can substitute russets, but they are more starchy and may absorb more liquid. The leeks should be thoroughly cleaned to remove any grit; slice them thinly and rinse well. Use only the white and light green parts, as the dark green leaves are tough and bitter.

Aged Swiss Gruyere is the classic cheese for this gratin, but you can also use Comte or Emmental. Grating your own cheese from a block is important because pre-shredded cheese contains anti-caking agents that prevent smooth melting.

For the truffle oil, use a good-quality one and add it just before serving to preserve its aroma. If you don't have truffle oil, you can omit it or use a small amount of olive oil. A cast iron skillet is ideal, but any oven-safe skillet or baking dish will work.

• Yukon Gold potatoes: Russet potatoes (more starchy, slightly less creamy but still work well)
• Aged Swiss Gruyere: Comte or Emmental (similar nutty, melty quality)
• Truffle oil: Extra-virgin olive oil (omit for a non-truffle version)
• Heavy cream: Half-and-half (thinner, so reduce the final simmer time slightly)

Equipment

• 10-inch cast iron skillet
• Box grater
• Mandoline or sharp chef's knife
• Small saucepan
• Mixing bowl
• Aluminum foil