This Extra-Creamy Potato Casserole Wins the Award for Coziest Thanksgiving Side

Cacio e pepe, a beloved Roman pasta dish made with lots of Pecorino Romano and plenty of freshly ground black pepper, is a fan favorite for a reason. In it, a few ingredients come together to make something so satisfying — it’s simplicity at its best. This year, I wanted to bring the flavors of this iconic pasta to the Thanksgiving table in the form of potatoes. Meet your new favorite side dish: cacio e pepe potato gratin.

In the classic dish, finely grated Pecorino Romano gets tossed with al dente pasta — and some starchy pasta water — to yield a rich and creamy sauce. In this version, I toss thinly sliced potatoes with a cacio e pepe-flavored cream sauce made with butter, shallot, heavy cream, water, and cheese.

Black pepper is the only spice in this dish, so you’ll see that the recipe calls for a lot of it. Many of us tend to add pepper to a dish alongside salt, almost as an afterthought. A dish like this brings pepper to the forefront, highlighting its spicy bite, and also its floral flavor notes.

Layered into a baking dish and roasted until the gratin is browned and bubbly, this super-flavorful side is sure to impress your guests.

If You’re Making Cacio e Pepe Potato Gratin, a Few Tips

• Switch up the potatoes. I call for Yukon Gold potatoes, but you can use Russet potatoes instead.

• Slice the potatoes into 1/8-inch-thick rounds. This ensures that the potatoes cook evenly and helps them absorb the cream sauce.

• Make it ahead. You can par-cook the gratin ahead of when you plan to serve it. Bake the assembled dish for 45 minutes, uncover, and let cool completely before placing it in the refrigerator covered. The day of, bake the gratin for 20 minutes to warm it up, then increase the oven temperature, uncover the dish, and continue to bake until browned on top.

Cacio e Pepe Potato Gratin Recipe

Thinly sliced potatoes get tossed with a flavorful cream sauce, layered with plenty of Pecorino Romano, and baked until browned and bubbly.

Prep time 30 minutes

Cook time 1 hour 20 minutes

Serves8

Ingredients

• 1 1/2 cups

  finely grated Pecorino Romano cheese (about 6 ounces), divided

• 3 1/2 pounds

  Yukon Gold potatoes

• 1

  large shallot

• 2 tablespoons

  unsalted butter, divided plus more for the baking dish

• 1 tablespoon

  freshly ground black pepper, plus more for as needed

• 2 tablespoons

  kosher salt

• 2 cups

  heavy cream

• 1/4 cup

  water

Instructions

1. Arrange a rack in the middle of the oven and heat the oven to 375ºF. Coat a 9x13-inch or other 3-quart baking dish with butter.

2. Finely grate 6 ounces Pecorino Romano cheese if needed, or measure out 1 1/2 cups store-bought grated. Peel and thinly slice 3 1/2 pounds Yukon Gold potatoes with a knife or on a mandolin into 1/8-inch-thick rounds. Place in a large bowl. Finely chop 1 large shallot (scant 1 cup).

3. Melt 2 tablespoons unsalted butter in a small saucepan over medium heat. Add the shallot and season with 1 tablespoon freshly ground black pepper and 2 teaspoons kosher salt. Cook, stirring frequently, until the shallot is soft and translucent and the pepper is fragrant, 3 to 4 minutes.

4. Add 2 cups heavy cream and 1/4 cup water, stir to combine, and bring to a gentle simmer. Remove the pan from the heat. While whisking constantly, add 1 cup of the cheese a few tablespoons at a time, and whisk until the sauce is smooth.

5. Transfer the sauce to the bowl of potatoes and toss thoroughly to coat. Arrange half of the potato mixture in the baking dish in an even layer. Sprinkle with 1/4 cup of the cheese and a few generous grinds of black pepper. Arrange the remaining potato mixture over the top. Pour the remaining sauce from the bowl evenly over the potatoes. Sprinkle with the remaining 1/4 cup cheese and grind another generous amount of black pepper over the surface.

6. Cover the baking dish tightly with aluminum foil. Bake until the potatoes are tender, about 45 minutes.

7. Uncover the baking dish. Increase the oven temperature to 425ºF. Bake until the top is browned and the sauce has thickened slightly, 20 to 25 minutes more. Let the gratin cool for 10 minutes before serving, the sauce will thicken as it cools.

Recipe Notes

Make ahead: The gratin can be made ahead through the first 45-minute baking step. Uncover and let cool completely. Cover the baking dish tightly with aluminum foil and refrigerate for up to 5 days. To reheat, remove from the oven about one hour before and heat the oven to 375ºF. Bake, still covered, for 20 minutes. Uncover and proceed with increasing the oven temperature and baking for the remaining time.

Substitutions: Russet potatoes can be substituted for the Yukon Golds. One small yellow onion can be substituted for the shallot. Half-and-half can be substituted for the heavy cream. Some or all of the Pecorino Romano cheese can be replaced with equal amounts of grated Parmesan cheese.

Storage: Leftovers can be refrigerated in an airtight container for up to 5 days or frozen for up to 3 months. Thaw overnight in the refrigerator.