Cheesy Root Vegetable Gratin is a warm, comforting dish filled with layers of tender root veggies like potatoes, carrots, and parsnips, all baked in a creamy cheese sauce until golden and bubbling. The combination of earthy vegetables with rich, melted cheese makes every bite a cozy, tasty treat.
I love making this gratin when I want something that feels like a hug on a plate. It’s simple to put together but feels special enough for family dinners or holiday meals. Plus, I always take a little extra time to let the cheese get perfectly browned on top—that’s the best part in my opinion!
One of my favorite ways to serve this dish is alongside a fresh green salad to add some crunch and brightness. It’s such a crowd-pleaser, and I find that it works well as a main dish or as a side with roasted chicken or pork. Every time I make it, people keep asking for the recipe, which always makes me smile.
Key Ingredients & Substitutions
Potatoes & Sweet Potatoes: They give a creamy texture and natural sweetness. Yukon Gold potatoes work great for creaminess, but russets or red potatoes are fine too. If you can’t find sweet potatoes, try using carrots or pumpkin for a similar sweet note.
Beets: Beets add color and an earthy flavor. If you dislike beets, try using parsnips or turnips instead—they bring a mild sweetness and nice texture.
Cream & Milk: The creaminess is key to keeping the vegetables tender and rich. Heavy cream is best, but you can substitute half-and-half or whole milk for a lighter version. Just expect a less rich sauce.
Gruyère Cheese: I love Gruyère for its nutty, melting quality, but Parmesan or mozzarella are good alternatives. For dairy-free, try a plant-based cheese that melts well or sprinkle some nutritional yeast for a cheesy flavor.
Thyme: Fresh thyme adds an herbal brightness. If you don’t have thyme, rosemary or sage also pair nicely with root vegetables.
How Can I Get Perfectly Tender and Well-Layered Vegetables?
Slicing the vegetables thinly and evenly is crucial. I use a mandoline slicer to get uniform slices about 1/8 inch thick—that helps them cook evenly. Here’s my process:
- Peel and wash all veggies.
- Slice each vegetable into thin, even rounds.
- Layer them tightly and slightly overlapping inside the dish for a pretty, even bake.
- Pour the cream mixture slowly to avoid washing away the layers.
- Cover with foil during early baking to steam and soften the veggies, then bake uncovered so the top gets golden and bubbly.
Letting the gratin rest after baking allows the cream to thicken and flavors to blend. This step is easy to miss but makes a big difference in taste and texture.
Equipment You’ll Need
- Mandoline slicer – makes thin, even slices fast and safe, which helps veggies cook evenly.
- Large gratin or casserole dish – ideal for layering and baking your veggies with cheese and cream.
- Mixing bowl – to whisk together cream, milk, herbs, and seasoning easily.
- Aluminum foil – you’ll cover the dish while baking to keep veggies tender.
- Cheese grater – to shred cheese evenly for melting perfectly on top.
Flavor Variations & Add-Ins
- Swap beets for thinly sliced turnips or parsnips if you want a milder, sweet earthiness.
- Add cooked bacon or pancetta between layers for a smoky, meaty touch.
- Mix in fresh herbs like rosemary or sage for a different herbal aroma.
- Try swapping Gruyère for sharp cheddar to get a bolder cheese flavor.
How to Make Cheesy Root Vegetable Gratin
Ingredients You’ll Need:
Vegetables:
- 2 large potatoes, peeled and thinly sliced
- 2 large sweet potatoes or yams, peeled and thinly sliced
- 2 large beets, peeled and thinly sliced
- 1 medium turnip or parsnip, peeled and thinly sliced (optional)
For the Sauce and Topping:
- 2 cups heavy cream
- 1 cup whole milk
- 2 garlic cloves, minced
- 1 ½ cups grated Gruyère cheese (or a mix of Gruyère and Parmesan)
- 1 teaspoon fresh thyme leaves (or ½ teaspoon dried thyme)
- Salt and freshly ground black pepper to taste
- Butter for greasing the baking dish
Time You’ll Need:
This dish takes about 15 minutes to prep, plus 1 hour to bake. Add an extra 10 minutes resting time after baking before serving. So, roughly 1 hour and 25 minutes from start to finish.
Step-by-Step Instructions:
1. Prepare the Oven and Dish:
Preheat your oven to 375°F (190°C). Butter a large oval or rectangular gratin dish to keep the vegetables from sticking and add a delicious hint of richness.
2. Make the Cream Mixture:
In a mixing bowl, whisk together the heavy cream, whole milk, minced garlic, thyme, salt, and pepper. This creamy sauce will soak into the vegetables and make the gratin beautifully rich.
3. Layer the Vegetables:
Arrange the sliced root vegetables—potatoes, sweet potatoes, beets, and the optional turnip or parsnip—in alternating layers in the dish. Slightly overlap each slice to create a pretty and even pattern covering the bottom and sides of the dish.
4. Add Cream and Cheese:
Pour the cream mixture evenly over the layered vegetables. Sprinkle half of the grated cheese on top to start forming a cheesy crust.
5. Bake Covered:
Cover the dish tightly with aluminum foil and bake for 45 minutes. This helps the vegetables steam and soften well inside the sauce.
6. Finish Baking Uncovered:
Remove the foil and sprinkle the remaining cheese over the top. Bake uncovered for about 25-30 minutes more, until the vegetables are tender, and the cheese crust on top is golden, bubbly, and delicious.
7. Rest and Serve:
Take the gratin out of the oven and let it rest for 10 minutes. This lets the sauce thicken slightly and flavors settle. Garnish with a few fresh thyme leaves, if you like, and serve warm.
Can I Use Frozen Vegetables for This Gratin?
While fresh is best for texture and flavor, you can use frozen root vegetables if needed. Be sure to thaw them completely and pat dry to avoid excess water, which can make the gratin watery.
Can I Make This Gratin Ahead of Time?
Yes! Prepare the gratin up to the point before baking, cover it tightly, and refrigerate for up to 24 hours. When ready, bake covered for about 50 minutes, then uncover and bake until golden and bubbly.
How Should I Store Leftovers?
Store any leftover gratin in an airtight container in the fridge for up to 3 days. Reheat gently in the oven or microwave, covering it to keep moisture in.
Can I Use Different Cheeses?
Absolutely! Gruyère adds a nutty flavor but Parmesan, cheddar, or mozzarella are delicious alternatives. For a dairy-free option, try a plant-based melting cheese or sprinkle nutritional yeast for cheesy notes.
