Rutabaga, Celery Root, and Potato Gratin


This recipe for a three-root gratin is reinvigorated by a hearty combination of rutabaga and celery root. Rutabaga and celery root bring an earthy depth and an engaging, subtle sweetness, giving a classic gratin a flavorful lift. Classic gratins lean on heaps of Gruyère; here, robust Parmigiano-Reggiano cuts in with more intense flavor, accentuating the root vegetables instead of smothering them. The salty bite of the Parmesan, along with the brightness from the celery root, transforms what could be a stodgy side into a reimagined classic that will have you coming back for seconds. Use a mandoline to slice the vegetables for best results.

Root vegetable gratin
Photo: Photo by Greg DuPree / Food Styling by Torie Cox / Prop Styling by Christine Keely
Active Time:
30 mins
Total Time:
1 hrs
4 to 6


  • 1 pound medium rutabaga, trimmed, peeled, and cut into 1/8-inch-thick slices

  • 1 pound medium Yukon Gold potatoes, peeled and cut into 1/8-inch-thick slices

  • 8 ounces small celery root, trimmed, peeled, and cut into 1/8-inch-thick slices

  • 1 3/4 cups heavy cream

  • 6 (5-inch) thyme sprigs, tied with kitchen twine, plus fresh thyme leaves, for garnish

  • 1 tablespoon kosher salt

  • 1/2 teaspoon black pepper

  • Unsalted butter, for greasing baking dish

  • 1 ounce Parmesan cheese, grated (about  1/4 cup)


  1. Preheat oven to 400°F with rack in middle position. Place rutabaga, potatoes, celery root, cream, and thyme sprigs in a large saucepan. Cover and cook over medium, turning vegetables occasionally, until cream just begins to bubble around edges of pan. Continue cooking, turning vegetables occasionally, until vegetables are tender on the outside but still crunchy in the center, 12 to 15 minutes, reducing heat as needed to maintain a very gentle simmer. Remove from heat; stir in salt and pepper.

  2. While vegetable mixture cooks, lightly grease a 2-quart baking dish or 10-inch cast-iron skillet with butter, and place on a rimmed baking sheet.

  3. Remove and discard thyme sprigs from vegetable mixture. Spoon half of vegetable mixture into prepared pan; sprinkle with 2 tablespoons cheese. Top with remaining vegetable mixture, pressing down gently to even top layer. Sprinkle with remaining 2 tablespoons cheese.

  4. Place baking sheet with gratin in preheated oven. Bake until mixture is bubbling and vegetables are tender, about 15 minutes. Increase oven temperature to broil (do not remove gratin from oven). Broil on middle rack until golden brown in spots, 1 to 2 minutes. Remove from oven; garnish with thyme leaves. Let cool 15 minutes.

Make Ahead

Gratin can be assembled through step 3 and refrigerated overnight. Let gratin come to room temperature before baking.

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