This Cheesy Root Vegetable Gratin layers tender potatoes, sweet parsnips, and earthy turnips under a golden blanket of cheese. I love serving it at Thanksgiving, where its creamy texture and crisp top bring something cozy and colorful to the holiday table.
Why You’ll Love This Cheesy Root Vegetable Gratin
This gratin is hearty enough to feel special, yet simple to prepare with familiar fall vegetables. The slices bake in a garlicky cream sauce until tender, while a mix of Gruyère and Parmesan adds savory flavor and a beautifully browned top. You can assemble it ahead, then bake it while you finish the rest of your Thanksgiving menu.
Cheesy Root Vegetable Gratin Ingredients & Substitutions
- 1 pound Yukon Gold potatoes, peeled
- 12 ounces sweet potato, peeled
- 12 ounces parsnips, peeled
- 8 ounces turnips, peeled
- 1 tablespoon unsalted butter, for greasing the baking dish
- 1 ½ cups heavy cream
- ½ cup whole milk
- 2 garlic cloves, finely grated or minced
- 1 teaspoon fresh thyme leaves, plus a little more for garnish
- ¾ teaspoon kosher salt
- ¼ teaspoon black pepper
- Pinch of ground nutmeg
- 1 ½ cups shredded Gruyère cheese, divided
- ½ cup finely grated Parmesan cheese, divided
For a different mix, swap in peeled rutabaga for some of the turnip or parsnip. Gruyère can be replaced with sharp white cheddar. Use half-and-half in place of the cream for a lighter sauce, though the gratin will be a little less rich.
Step-by-Step Instructions to Make Cheesy Root Vegetable Gratin
1. Prepare the oven and dish
Heat the oven to 375°F (190°C). Butter a 9-by-13-inch baking dish, or a similar 3-quart oven-safe dish. Set the dish aside.
2. Slice the vegetables
Slice the potatoes, sweet potato, parsnips, and turnips into thin rounds, about ⅛ inch thick. A mandoline makes even slices, but a sharp knife works well too. Keep the slices similar in thickness so they cook at the same pace.
3. Make the cream mixture
In a bowl, whisk together the heavy cream, milk, garlic, thyme, salt, pepper, and nutmeg. Stir in 1 cup of the Gruyère and ¼ cup of the Parmesan.
4. Layer the vegetables
Arrange the vegetable slices in overlapping layers in the prepared dish, alternating the different vegetables as you go. Pour the cream mixture evenly over the top, gently nudging the slices so the sauce settles between them.
5. Bake until tender and golden
Cover the dish tightly with foil and bake for 40 minutes. Remove the foil, sprinkle over the remaining Gruyère and Parmesan, then bake uncovered for 25 to 35 minutes, until the vegetables are tender when pierced with a knife and the top is bubbling and golden. Rest for 10 minutes before serving.
Tips for Success
- Slice the vegetables evenly. Thin, consistent slices cook more reliably and make neat, tender layers.
- Check doneness in the center of the dish, where the vegetable layers are deepest.
- If the top browns before the vegetables are tender, loosely cover the dish with foil and continue baking.
- Let the gratin rest before serving. This gives the cream sauce a few minutes to settle, making portions easier to lift.
- For the best texture, grate the cheese yourself from a block. It melts smoothly into the sauce and over the top.
Variations of Cheesy Root Vegetable Gratin
Try a mix of carrots, rutabaga, and potatoes for another colorful combination. For a more herb-forward flavor, add a teaspoon of chopped fresh rosemary or sage to the cream. You can also use sharp white cheddar instead of Gruyère, or add a thin layer of caramelized onions between the vegetables for extra sweetness.
Serving Suggestions: What to Pair with Cheesy Root Vegetable Gratin
This gratin belongs beside classic Thanksgiving dishes such as roast turkey, green beans, Brussels sprouts, and cranberry sauce. It also pairs nicely with roast chicken or a simple green salad. Since it is rich and filling, serve it in modest portions alongside lighter vegetable sides.
Storage & Reheating Instructions
Cool leftovers, cover the baking dish, and refrigerate for up to 4 days. Reheat individual portions in the microwave, or warm the covered dish in a 325°F (165°C) oven until heated through. Remove the cover for the final few minutes if you would like to crisp the top again. For make-ahead prep, assemble the gratin, cover, and refrigerate for up to 1 day before baking. Add a little extra baking time if it goes into the oven cold.
Memories Made Around the Table
I always enjoy the moment a bubbling gratin arrives at the Thanksgiving table, still warm from the oven and fragrant with thyme and toasted cheese. Its colorful layers feel festive, and it is the kind of side dish that invites everyone to take just one more spoonful. I like to set it near the turkey so guests can pair a creamy bite with all their favorite holiday sides.
FAQs
Can I make Cheesy Root Vegetable Gratin ahead of time?
Yes. Assemble it up to a day in advance, cover, and refrigerate. Bake it straight from the refrigerator, allowing extra time for the center to heat and the vegetables to become tender.
How do I know when the gratin is done?
The top should be golden and bubbling, and a knife should slide easily through the vegetables in the center of the dish. If the vegetables are still firm, cover loosely with foil and bake a little longer.
Can I freeze leftovers?
You can freeze portions in airtight containers, though cream-based sauces may change texture slightly after thawing. Thaw overnight in the refrigerator and reheat gently in the oven for the best result.
What other cheeses work in this gratin?
Sharp white cheddar, fontina, or a blend of mozzarella and Parmesan can stand in for Gruyère. Choose a cheese that melts well and has enough flavor to complement the root vegetables.
Final Thoughts
Cheesy Root Vegetable Gratin is a comforting Thanksgiving side with tender layers, a creamy garlic sauce, and a crisp, savory top. Prepare it for a holiday gathering or enjoy it alongside a weeknight roast, and let the seasonal vegetables shine.
Cheesy Root Vegetable Gratin
Equipment
- 1 9-by-13-inch baking dish or similar 3-quart oven-safe dish
- 1 Aluminum foil
- 1 Mixing Bowl
- 1 Whisk
- 1 Mandoline optional; a sharp knife also works
Ingredients
- 1 pound Yukon Gold potatoes peeled
- 12 ounces sweet potato peeled
- 12 ounces parsnips peeled
- 8 ounces turnips peeled
- 1 tablespoon unsalted butter for greasing the baking dish
- 1.5 cups heavy cream
- 0.5 cup whole milk
- 2 cloves garlic finely grated or minced
- 1 teaspoon fresh thyme leaves plus a little more for garnish
- 0.75 teaspoon kosher salt
- 0.25 teaspoon black pepper
- 1 pinch ground nutmeg
- 1.5 cups shredded Gruyère cheese divided
- 0.5 cup finely grated Parmesan cheese divided
Instructions
- Heat the oven to 375°F (190°C). Butter a 9-by-13-inch baking dish, or a similar 3-quart oven-safe dish.
- Slice the potatoes, sweet potato, parsnips, and turnips into thin rounds, about ⅛ inch thick. Use a mandoline or sharp knife, keeping the slices similar in thickness.
- In a bowl, whisk together the heavy cream, milk, garlic, thyme, salt, pepper, and nutmeg. Stir in 1 cup of the Gruyère and ¼ cup of the Parmesan.
- Arrange the vegetable slices in overlapping layers in the prepared dish, alternating the different vegetables. Pour the cream mixture evenly over the top, gently nudging the slices so the sauce settles between them.
- Cover the dish tightly with foil and bake for 40 minutes. Remove the foil and sprinkle over the remaining Gruyère and Parmesan. Bake uncovered for 25 to 35 minutes, until the vegetables are tender when pierced with a knife and the top is bubbling and golden. Rest for 10 minutes before serving.