Horseradish Potato Gratin

• unsalted butter for the baking dish, at room temperature
• 3 cups heavy cream
• 1/4 cup prepared horseradish
• 1/4 teaspoon ground nutmeg
• kosher salt and black pepper
• 3 pounds russet potatoes (about 6), peeled and thinly sliced

Directions

1. Heat oven to 375° F. Butter a shallow 3-quart baking dish. In a large bowl, combine the cream, horseradish, nutmeg, 1 1/2 teaspoons salt, and 3/4 teaspoon pepper. Add the potatoes and toss to coat.
2. Transfer the potato mixture to the prepared baking dish, pressing gently to submerge the potatoes. Cover the dish with foil, place on a rimmed baking sheet, and bake for 25 minutes. Remove the foil and bake until the potatoes are tender and the top is golden, 50 to 65 minutes.