Potato & Celery Root Gratin with Leeks
A luxurious layered gratin combining thinly sliced potatoes and celery root with tender leeks, all bathed in herb-infused cream and topped with melted Gruyère cheese. This elegant side dish features a perfect balance of earthy root vegetables and rich, creamy texture.
Ingredients
- •3 cups heavy cream
- •2 cloves garlic
- •1 sprig thyme
- •2 tablespoons unsalted butter
- •3 whole leeks
- •1 to taste Kosher salt
- •2 pounds russet potatoes
- •1 pound celery root
- •2 cups grated Gruyère
- •1 to taste black pepper
Cooking Instructions
- 1.
Preheat oven to 350°F. Heat cream, garlic, and thyme sprig in a medium saucepan just until bubbles begin to form around edge of pan. Remove from heat; set aside to steep.
10 min
- 2.
Melt 1 tablespoon butter in a medium skillet over medium heat. Add leeks; season with salt and cook, stirring often, until tender (do not brown), 10-12 minutes. Transfer to a small bowl and set aside.
12 min
- 3.
Butter a 3-quart gratin dish with remaining 1 tablespoon butter. Layer 1/3 of potato slices and 1/3 of celery root slices evenly over bottom of baking dish. Cover with 1/3 of leeks, then 1/3 of Gruyère. Sprinkle with salt, pepper, and 1 teaspoon thyme leaves. Repeat layers twice more. Strain cream mixture into a medium pitcher and pour over vegetables.
15 min
- 4.
Set gratin dish on a large rimmed baking sheet and cover tightly with foil. Bake for 1 hour. Carefully remove foil; continue baking until top is golden brown and sauce is bubbling, 25-30 minutes. DO AHEAD: Can be made 2 hours ahead. Let stand at room temperature. Tent with foil and rewarm in a 300° oven until hot, about 20 minutes.
90 min
