I always reach for this recipe when I want a dish that brings both flavor and visual wow-factor to the table. The vegetables bake until perfectly tender, absorbing the cream and seasoning while the cheese on top gets irresistibly golden and bubbly. It’s vegetarian-friendly and a great make-ahead option, which saves me time during busy holiday prep. Plus, the leftovers are just as good the next day.
Ingredients
(Here’s a tip: Check out the full list of ingredients and measurements in the recipe card below.)
1 tablespoon unsalted butter, softened 1–2 long sweet potatoes (about 2 inches thick), peeled 3–4 large parsnips, ends trimmed and peeled 3–5 small beets, peeled 14 tablespoons heavy cream, divided 4 ounces grated Parmesan, divided 1 tablespoon fresh minced thyme, divided, plus more for garnish 1 garlic clove, minced 1 ounce shredded Gruyère Salt and pepper to taste
Directions
I preheat the oven to 400˚F and grease a 3-quart baking dish with the softened butter.
I slice the sweet potatoes, parsnips, and beets into very thin rounds using a mandoline for even slices. Then, I separate them into three bowls by type.
I pour 4 tablespoons of cream over the sweet potatoes and parsnips, and 2 tablespoons over the beets.
I add ½ ounce of Parmesan and 1 teaspoon minced thyme to each bowl, seasoning generously with salt and pepper. I toss each batch of vegetables until well coated.
I pour the remaining ¼ cup of cream into the base of the baking dish and sprinkle it with ½ ounce of Parmesan and the minced garlic.
I stack the sweet potato slices and place them standing on a bias at the top of the dish, followed by a row of parsnips, then beets. I repeat the pattern until the dish is filled with six rows.
I season the top with more salt and pepper and sprinkle with the remaining Parmesan.
I cover the dish with foil and bake for 30 minutes, until the vegetables start to soften.
I uncover the dish, top it with shredded Gruyère, and return it to the oven for 18–20 minutes, until the vegetables are fork-tender and the top is golden and bubbly.
I finish with a sprinkle of fresh thyme before serving.
Servings and timing
This recipe makes enough for 8 servings. It takes about 15 minutes to prepare and 50 minutes to cook, for a total of just over an hour. It’s a perfect side dish for a holiday dinner or a cozy weekend meal.
Variations
Sometimes I swap out the vegetables for whatever I have on hand—turnips, rutabaga, or carrots work beautifully. I’ve also tried this with a mix of cheeses like white cheddar or fontina for a different twist. If I want a lighter version, I use whole milk instead of cream, but I keep in mind that the result won’t be as thick or rich. I can even add layers of sautéed onions or leeks for an extra savory touch.
storage/reheating
I often make this gratin a day ahead and store it tightly wrapped in foil in the refrigerator. When I’m ready to bake, I place it directly in the oven, adding 5–7 minutes to the baking time while it’s still covered. Leftovers keep well in the fridge for up to 3 days. I reheat individual servings in the microwave or rewarm the whole dish in the oven at 350°F until heated through. To avoid beets bleeding into the cream, I make sure they’re lightly coated and not oversaturated before layering.
FAQs
Can I make this dish ahead of time?
Yes, I often prep it the day before. I just cover it tightly with foil and refrigerate. I add a few extra minutes to the bake time when cooking it straight from the fridge.
How can I prevent the beets from bleeding?
I make sure the beets are just lightly coated in cream and not overly saturated. It helps keep the layers looking sharp and colorful.
Can I use a different cheese?
Definitely. I’ve used white cheddar, fontina, or even mozzarella when I want a milder or different cheesy flavor. Gruyère just adds a nice nuttiness.
What if I don’t have a mandoline?
I can slice the vegetables thinly by hand using a sharp knife. It takes a little more time, but it still works well.
Is it okay to use milk instead of cream?
Yes, whole milk can be used, but I notice the mixture won’t thicken as much and the gratin won’t be quite as rich. It’s still tasty, though!
Conclusion
This cheesy root vegetable gratin is one of my favorite dishes to bring to the table during holidays or special dinners. It’s warm, creamy, and packed with earthy flavors that pair perfectly with a variety of main courses. The vibrant layers of vegetables look beautiful and taste even better. Whether I’m entertaining or just making something special for myself, this gratin always feels like a celebration.
This cheesy root vegetable gratin is a stunning and delicious side dish made with sweet potatoes, beets, and parsnips. Perfect for Thanksgiving or any special meal, it’s creamy, savory, and packed with flavor.
Author:Ella
Prep Time:15 minutes
Cook Time:50 minutes
Total Time:1 hour 5 minutes
Yield:8 servings
Category:Side Dish
Method:Baking
Cuisine:French
Diet:Vegetarian
Ingredients
1 tablespoon unsalted butter, softened
1–2 long sweet potatoes (about 2 inches thick), peeled
3–4 large parsnips, ends trimmed and peeled
3–5 small beets, peeled
14 tablespoons heavy cream, divided (whole milk can be used, but results will be less creamy)
4 ounces grated Parmesan, divided
1 tablespoon fresh minced thyme, divided (plus more for garnish)
1 garlic clove, minced
1 ounce shredded Gruyere
Salt and pepper, to taste
Instructions
Preheat oven to 400°F (200°C). Grease a 3-quart baking dish with butter.
Slice sweet potatoes, parsnips, and beets into very thin rounds using a mandoline, and place each into separate bowls.
Pour 4 tablespoons of cream over the sweet potatoes and parsnips, and 2 tablespoons over the beets.
Add ½ ounce Parmesan and 1 teaspoon thyme to each bowl. Season generously with salt and pepper and toss to coat.
Pour ¼ cup of cream into the bottom of the baking dish. Sprinkle with ½ ounce Parmesan and the minced garlic.
Arrange the vegetables upright in rows, alternating sweet potatoes, parsnips, and beets to create a pattern.
Season the top with salt, pepper, and remaining Parmesan. Cover with foil.
Bake covered for 30 minutes, or until vegetables are soft.
Uncover and top with shredded Gruyere. Return to oven and bake 18–20 minutes, until cheese is melted and lightly browned.
Garnish with fresh thyme leaves and serve.
Notes
Makes 1 (3-quart) casserole.
Can be made 1 day ahead; refrigerate covered and bake with 5–7 minutes added time.
Beets may bleed when prepped in advance—minimize cream exposure to reduce this.
To avoid color bleeding, lightly coat beets in cream and avoid excess liquid in the baking dish.
