This truffled potatoes au gratin is made with thinly sliced potatoes bathed in a fragrant béchamel sauce.
Truffle zest adds a rich, umami flavor to this truffled potatoes au gratin.
This is a stunning side dish to add to your Thanksgiving lineup! It’s rich, creamy, with subtle, sweet, and spiced umami undertones thanks to nutmeg and truffle zest.
What you need
- Béchamel sauce: Butter, all-purpose flour, whole milk, truffle zest, nutmeg, salt, and white pepper.
- Potatoes: Yukon Gold potatoes, nutmeg, truffle zest, salt, and pepper.
How to make it
Step 1: Prepare the potatoes.
A mandolin makes the work much easier, but you can also use a sharp knife. Just be sure to slice the potatoes as thinly as you can. Once the potatoes are sliced, toss them with salt, black pepper, nutmeg, and truffle zest.
Step 2: Make the béchamel.
Warm the milk and cook the flour in melted butter. Slowly add the milk, whisking continuously, until fully incorporated. Simmer until the sauce thickens and coats the back of a spoon. Season with nutmeg, truffle zest, salt, and white pepper.
Step 3: Assemble the gratin.
Layer the potatoes on the bottom of a greased oval baking dish. Spoon a few ladles of the béchamel on top and smooth it into an even layer. Continue layering the potatoes and béchamel until all the ingredients have been used up. Be sure to reserve enough béchamel as a top layer for the gratin.
Step 4: Bake the gratin.
Cover the baking dish with foil and transfer to a preheated oven. Bake for 1 hour before removing the foil and allowing the gratin to bake until the top is bubbly and browned. Remove from the oven and let stand for 15 minutes.
Step 5: Serve.
Spoon the gratin onto plates and serve with your favorite roasted protein.
Truffled Potato Gratin
Ingredients
Béchamel sauce:
- 4 tablespoons butter
- 4 tablespoons all-purpose flour
- 4 cups whole milk
- 2 teaspoons truffle zest
- 1 teaspoon nutmeg
- 1 teaspoon kosher salt
- White pepper
Potatoes:
- 4 Yukon Gold potatoes (about 2 pounds; peeled and sliced paper-thin)
- 1 teaspoon nutmeg
- 1 teaspoon truffle zest (divided)
- Kosher salt (to taste)
- Black pepper (to taste)
- Fresh thyme leaves (optional, for serving)
- Extra virgin olive oil (for greasing)
Instructions
Prepare potatoes:
- Preheat the oven to 400ºF.
- Pat the sliced potatoes dry with paper towels and then toss the potatoes with 1 teaspoon kosher salt, ½ teaspoon black pepper, 2 teaspoons truffle zest, and 1 teaspoon ground nutmeg. Set aside.
Make the béchamel:
- Add 4 cups whole milk to a small saucepan and turn the heat to low. In a large saucepan, melt 4 tablespoons butter over medium heat. Once melted, add 4 tablespoons all-purpose flour and stir to incorporate.
- Cook the flour for 1 to 2 minutes until golden, but not overly browned. Whisk in the warm milk and continue whisking until smooth. Adjust the heat to medium to bring the mixture to a very low boil, and immediately turn the heat to low.
- Continue whisking as the sauce thickens. Cook for 2 to 3 minutes until the sauce coats the back of a spoon.
- Add 2 teaspoons truffle zest and 1 teaspoon nutmeg. Taste and season with kosher salt and a pinch of white pepper. Turn off the heat.
Assemble the potatoes au gratin:
- Grease the bottom and inside of a large casserole dish with extra virgin olive oil. Arrange a layer of overlapping potatoes along the bottom of the dish.
- Spoon a ladle or two of the béchamel on top and use the back of the ladle to evenly spread the sauce on top of the potatoes. Continue layering with potatoes and the béchamel until no ingredients remain. See Note 1.
Bake the gratin:
- Cover the casserole dish with foil and transfer to the oven. Bake for 1 hour. After 1 hour, remove the foil and bake for an additional 20 minutes or until the top of the casserole is golden. Remove from the oven and sprinkle the casserole with fresh thyme leaves if desired. Let stand for 15 minutes before serving.
To serve:
- Divide the potatoes au gratin between plates and enjoy with your favorite protein.
