This Cheesy Root Vegetable Gratin layers tender potatoes, parsnips, carrots, and celery root under a creamy garlic sauce and golden cheese. I love serving it at Thanksgiving because it feels special, feeds a crowd, and can be prepared ahead.
Why You’ll Love This Cheesy Root Vegetable Gratin
Each bite brings together sweet, earthy root vegetables and a rich, savory sauce, with a bubbling cheese topping for extra comfort. The vegetables make a colorful change from familiar holiday sides, and the gratin pairs easily with roast turkey or a vegetarian main. You can assemble it in advance, then bake it when you’re ready to serve.
Cheesy Root Vegetable Gratin Ingredients & Substitutions
- 1 tablespoon unsalted butter, softened, for greasing the baking dish
- 1 pound Yukon Gold potatoes, peeled and thinly sliced
- 12 ounces parsnips, peeled and thinly sliced
- 12 ounces carrots, peeled and thinly sliced
- 12 ounces celery root, peeled and thinly sliced
- 1 1/2 cups heavy cream
- 1 cup whole milk
- 2 garlic cloves, finely minced
- 1 teaspoon fresh thyme leaves, or 1/2 teaspoon dried thyme
- 1 teaspoon kosher salt
- 1/2 teaspoon freshly ground black pepper
- 1 1/2 cups shredded Gruyère cheese, divided
- 1/2 cup finely grated Parmesan cheese
Gruyère melts smoothly and has a lovely savory flavor. You can use sharp cheddar instead, or replace the celery root with more potatoes or parsnips. A mandoline makes even slices, but a sharp knife works well too.
Step-by-Step Instructions to Make Cheesy Root Vegetable Gratin
1. Prepare the vegetables and dish
Heat the oven to 375°F (190°C). Butter a 9-by-13-inch baking dish. Peel the vegetables and slice them about 1/8 inch thick so they cook evenly.
2. Make the cream mixture
In a large bowl, whisk together the cream, milk, garlic, thyme, salt, and pepper. Add the sliced vegetables and toss to coat them well.
3. Layer the gratin
Arrange the vegetable slices in overlapping layers in the prepared dish. Pour any remaining cream mixture over the top. Cover tightly with foil and bake for 40 minutes.
4. Add cheese and finish baking
Remove the foil and sprinkle the gratin with the Gruyère and Parmesan. Bake uncovered for 20 to 25 minutes, until the vegetables are tender when pierced with a knife and the top is golden and bubbling. If the top needs more color, broil briefly while watching closely.
5. Rest before serving
Let the gratin rest for 10 to 15 minutes before serving. This gives the creamy sauce time to settle and makes it easier to scoop.
Tips for Success
- Slice the vegetables to a similar thickness so they finish cooking at the same time.
- Keep the baking dish covered during the first part of baking to help the roots turn tender.
- Check the center with a thin knife before adding the cheese. If the vegetables still feel firm, cover and bake a little longer.
- Let the gratin rest before serving. The sauce thickens as it cools slightly.
- Use a baking dish with enough room for the cream to bubble without spilling over.
Variations of Cheesy Root Vegetable Gratin
Try a mix of sweet potatoes and turnips for a different balance of sweetness and earthiness. For a brighter flavor, add a little finely grated lemon zest to the cream mixture. You can also tuck a few thinly sliced shallots between the vegetable layers or add a pinch of freshly grated nutmeg to the sauce.
Serving Suggestions: What to Pair with Cheesy Root Vegetable Gratin
Serve this gratin alongside roast turkey, roasted chicken, or a hearty lentil loaf. It also goes well with green beans, Brussels sprouts, or a crisp salad dressed with a tangy vinaigrette. For a Thanksgiving spread, pair it with other make-ahead sides to keep the final cooking schedule manageable.
Storage & Reheating Instructions
Cool leftovers, cover the dish, and refrigerate for up to 4 days. Reheat individual portions in the microwave, or cover the baking dish with foil and warm it in a 350°F (175°C) oven until hot. Remove the foil for the last few minutes if you’d like to refresh the cheesy top. You can assemble the gratin a day ahead, cover, and refrigerate it before baking. Let the chilled dish sit at room temperature for about 20 minutes while the oven heats, then bake until hot and tender, allowing extra time as needed.
Memories Made Around the Table
I love setting this gratin among the Thanksgiving sides and watching everyone spot the different vegetables in the creamy layers. It’s the kind of dish that invites a second helping, and the golden top always gets plenty of attention. I make room for it beside the turkey, then save any leftovers for an easy, comforting lunch the next day.
FAQs
Can I make Cheesy Root Vegetable Gratin ahead of time?
Yes. Assemble it, cover it, and refrigerate it for up to a day before baking. Add a little extra baking time if it goes into the oven cold, and check that the vegetables are tender before serving.
How do I know when the gratin is done?
The top should be golden and bubbling, and a thin knife should slide easily into the vegetables in the center of the dish.
Can I use different root vegetables?
Yes. You can swap in turnips or sweet potatoes, or use extra potatoes, carrots, or parsnips. Slice any replacements evenly so they cook at a similar rate.
Can I freeze this gratin?
The texture is best when freshly baked or refrigerated and reheated. Cream-based sauces can separate after freezing, so freezing is not the best choice for this dish.
Final Thoughts
This Cheesy Root Vegetable Gratin makes a cozy, colorful addition to a Thanksgiving table. With tender vegetables, a simple cream sauce, and a golden cheese topping, it’s a side dish worth sharing.
Cheesy Root Vegetable Gratin
Equipment
- 1 9-by-13-inch baking dish
- 1 Large mixing bowl
- 1 Whisk
- 1 Aluminum foil
- 1 Knife or mandoline For slicing the vegetables
Ingredients
- 1 tablespoon unsalted butter softened, for greasing the baking dish
- 1 pound Yukon Gold potatoes peeled and thinly sliced
- 12 ounces parsnips peeled and thinly sliced
- 12 ounces carrots peeled and thinly sliced
- 12 ounces celery root peeled and thinly sliced
- 1.5 cups heavy cream
- 1 cup whole milk
- 2 cloves garlic finely minced
- 1 teaspoon fresh thyme leaves or 1/2 teaspoon dried thyme
- 1 teaspoon kosher salt
- 0.5 teaspoon freshly ground black pepper
- 1.5 cups shredded Gruyère cheese divided
- 0.5 cup finely grated Parmesan cheese
Instructions
- Heat the oven to 375°F (190°C). Butter a 9-by-13-inch baking dish. Peel the vegetables and slice them about 1/8 inch thick so they cook evenly.
- In a large bowl, whisk together the cream, milk, garlic, thyme, salt, and pepper. Add the sliced vegetables and toss to coat them well.
- Arrange the vegetable slices in overlapping layers in the prepared dish. Pour any remaining cream mixture over the top. Cover tightly with foil and bake for 40 minutes.
- Remove the foil and sprinkle the gratin with the Gruyère and Parmesan. Bake uncovered for 20 to 25 minutes, until the vegetables are tender when pierced with a knife and the top is golden and bubbling. If the top needs more color, broil briefly while watching closely.
- Let the gratin rest for 10 to 15 minutes before serving. This gives the creamy sauce time to settle and makes it easier to scoop.