Crispy Truffle Potato Gratin with Gruyere Cream Tips, FAQ & printable recipe

Tips for success

For the most even slices, use a mandoline set to 1/8 inch. If you're using a knife, try to keep the slices as uniform as possible; uneven slices will cook at different rates.

Soaking the sliced potatoes in cold water not only prevents browning but also removes some excess starch, which helps the gratin hold its shape. Be sure to pat them dry before layering, as excess water can dilute the cream.

When pouring the cream over the potatoes, shake the skillet gently to help it settle into all the nooks and crannies. You can also use a spatula to gently press down on the layers.

If you're making this ahead, you can assemble the gratin up to the point of baking, cover it, and refrigerate for up to 24 hours. Add about 10 minutes to the baking time if starting from cold.

Variations

• Add Sautéed Mushrooms: Sauté 8 oz sliced cremini mushrooms in butter until golden and add them in layers with the potatoes and leeks. This adds an earthy depth that pairs well with the truffle oil.
• Swap the Cheese: Use a mix of Gruyere and sharp white cheddar for a different flavor profile. The cheddar adds a sharper tang and melts just as well.
• Make it Herby: Add 1 tbsp chopped fresh rosemary or sage to the cream along with the thyme. This gives a more aromatic, woodsy note that complements the potatoes.
• Go Gluten-Free: This recipe is naturally gluten-free. Just ensure your truffle oil and cheese are certified gluten-free if you have celiac disease. Serve with a gluten-free main.

Storage and make-ahead

Fridge

Store leftover gratin in an airtight container in the refrigerator for up to 4 days. Reheat in a 350°F (175°C) oven for 10-15 minutes or microwave until hot.

Freezer

Freeze the baked gratin for up to 2 months. Wrap tightly in plastic wrap and foil. Thaw overnight in the fridge, then reheat in a 350°F (175°C) oven until hot.

Reheat

Reheat in a 350°F (175°C) oven for 10-15 minutes or microwave individual portions. The top may soften, but the flavor remains.

Leftover gratin can be stored in an airtight container in the refrigerator for up to 4 days. Let it cool completely before refrigerating. To reheat, place individual portions in a microwave or in a 350°F (175°C) oven until warmed through. The top may lose some crispness, but the flavor will remain delicious.

This gratin can be assembled up to 24 hours ahead. Prepare the potatoes, leeks, and cream as directed, layer everything in the buttered skillet, and pour the cream over.

Cover and refrigerate. When ready to bake, add about 10 to 15 minutes to the baking time, and check that the potatoes are fully tender before broiling with the cheese.

Serving ideas

Serve this gratin hot, straight from the skillet, for a rustic and impressive presentation. It pairs beautifully with roasted meats, such as beef, lamb, or pork, and also works well alongside a simple green salad for a vegetarian main.

The crispy edges and creamy center are best enjoyed immediately, while the cheese is still stretchy and the potatoes are piping hot.

For a more elegant presentation, you can slice the gratin into wedges and transfer them to individual plates using a wide spatula. Spoon any extra cream from the skillet over the top. Garnish with additional fresh thyme if desired. This dish is rich, so a modest portion is satisfying. Leftovers can be reheated and enjoyed the next day.

Frequently asked questions

Recipe card

Crispy Truffle Potato Gratin with Gruyere Cream

Prep 25 minCook 55 minRest 10 minTotal 1 h 30 minServes 6

Ingredients

• 2 lb Yukon Gold potatoes, sliced paper-thin
• 2 leeks, white and light green parts only, thinly sliced
• 8 oz aged Swiss Gruyere cheese, grated on a box grater
• 2 tbsp unsalted butter, softened
• 1 1/2 cups heavy cream
• 3 cloves garlic, minced
• 2 tsp fresh thyme leaves, plus more for topping
• 1 tsp kosher salt
• 1/2 tsp black pepper, freshly ground
• 1 tbsp truffle oil, for drizzling

Instructions

1. Heat the oven to 375°F (190°C). Slice the Yukon Gold potatoes into paper-thin rounds, about 1/8 inch thick, using a mandoline or a very sharp knife. Keep the slices in a bowl of cold water to prevent browning while you work. Thinly slice the leeks crosswise, using only the white and light green parts, and rinse them well to remove any grit. Pat the leeks dry with a clean kitchen towel.
2. Grate the aged Swiss Gruyere on the large holes of a box grater into a fresh pile of shredded cheese. Set aside. You should have about 2 cups of loosely packed grated cheese.
3. In a small saucepan, combine the heavy cream, minced garlic, fresh thyme leaves, kosher salt, and black pepper. Place over medium heat and bring to a gentle simmer, stirring occasionally. Let it bubble for 2 to 3 minutes until the cream is fragrant and slightly thickened. Remove from heat and set aside.
4. Generously coat the bottom and sides of a 10-inch cast iron skillet with the softened unsalted butter. Make sure every surface is well covered to prevent sticking and to add flavor.
5. Arrange the potato rounds in tight overlapping spirals in the buttered skillet, covering the bottom completely. Scatter a handful of the sliced leeks over the first layer. Repeat with another layer of potatoes, then leeks, until all potatoes and leeks are used, finishing with a neat layer of potatoes on top. Press down gently to compact the layers.
6. Pour the bubbling garlic thyme cream evenly over the layered potatoes, making sure it seeps down through all the layers. Gently shake the skillet to help the cream settle. The cream should come about three-quarters of the way up the sides.
7. Cover the skillet tightly with aluminum foil and bake in the preheated oven for 40 minutes. After 40 minutes, remove the foil and continue baking for 15 to 20 minutes more, until the top is golden brown and the potatoes are tender when pierced with a knife. The cream should be bubbling and slightly reduced.
8. Sprinkle the grated Gruyere evenly over the top of the gratin. Return the skillet to the oven and broil for 2 to 4 minutes, watching closely, until the cheese is melted, golden, and bubbling. The edges of the potatoes should be crispy and deeply browned.
9. Remove the skillet from the oven and let it rest for 10 minutes. Scatter fresh thyme leaves over the top and drizzle with truffle oil. The gratin will continue to set as it rests, making it easier to slice and serve.
10. Using a spatula or a large spoon, lift a golden cheese-stretching wedge straight from the skillet. Pull a crispy cheese-stretching portion to serve. Spoon any extra cream from the skillet over the top. Serve hot, directly from the skillet for a rustic presentation.

Contains: milk

Estimated nutrition per serving

Calories

420

Protein

14 g

Carbohydrates

28 g

Fat

29 g

Automatic estimate from the ingredient list, not laboratory-verified.