Cheesy Root Vegetable Gratin

This Cheesy Root Vegetable Gratin recipe might be one of my absolute favorites for This Cheesy Root Vegetable Gratin recipe might be one of my absolute favorites for fall and winter. It’s a great variation from the typical vegetable gratin. Usually vegetable gratins are made with a mixture of zucchini, tomato slices, and yellow squash, with some bread crumbs, cheese, and heavy cream mixed in. For our version we choose to focus on root vegetables, so beets, sweet potatoes, and parsnips. All of which are beautiful together because of the different colors! I know it’s a lot of peeling and slicing, but if you have a mandoline it’s makes the process so much easier. Plus, after you’re done slicing the vegetables, the rest of the dish is very easy to put together.

I love the subtly sweet and earthy flavors of this combination of root vegetables mixed together with the savory and salty shredded gruyère cheese, garlic, thyme, and heavy cream. It’s the perfect side dish to any thanksgiving, holiday or any cozy meal .

How to Make Our Cheesy Root Vegetable Gratin

Ingredients

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Process

Preheat oven.
Grease baking dish with butter.
Slice sweet potato, parsnips and beets into very thin rounds (using a mandoline is easiest) and transfer each vegetable to its own bowl.

A baking sheet with sliced root vegetables on it.

Pour heavy cream over each sweet potatoes and parsnips, and beets.
Top each bowl of sliced vegetables with some grated Parmesan cheese and some minced thyme. Season each bowl generously with salt and black pepper and toss together until all vegetable slices are well coated.
Pour remaining heavy cream into the greased baking dish and sprinkle with Parmesan and garlic.

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Bowls of root vegetables with cream and cheese.

A buttered baking dish with a layer of cream, parmesan, and garlic.

Grab a stack of sweet potatoes and line them standing up on a bias, at the top of the casserole dish.
Follow the sweet potatoes with a row of parsnips, followed by a row of beets.
Repeat with the remaining sweet potatoes, parsnips and beets, creating 6 rows of root vegetables.
Season top of gratin with salt, black pepper and sprinkle of remaining Parmesan.
Cover with aluminum foil and bake until vegetables are soft.

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A baking dish full of sliced root vegetables to make a root vegetable gratin.

A casserole dish with potatoes gratin and tin foil on top.

Uncover gratin and top with shredded gruyère.
Place gratin back into oven, uncovered, and continue to bake until vegetables are fork tender, cheese has melted and the top has lightly browned.
Finish cheesy root vegetable gratin with a sprinkle of fresh thyme leaves. Serve.

A baking dish with root vegetable gratin.

Root vegetable gratin with shredded cheese on top ready to go back into the oven.

Tools You Will Need

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Tips and Tricks for Cheesy Root Vegetable Gratin Success

Ensure all the vegetables are coated in cream so they don’t dry out. The beets should just be barely coated in cream because too much cream coating will result in them bleeding through the dish.
The aluminum foil should be tightly wrapped around the baking dish to allow the dish to steam a little and for the vegetables to get tender before uncovering it.
Wear gloves when handling beets to prevent them from staining your hands. If you do stain your hands, wash them with a blend of baking soda and warm water and vigorous rub them together. You may need a couple rounds of this process to completely remove the stains.
Keeping the slices as uniform in thickness as possible will greatly help even cooking throughout the gratin.
Using a mandoline will not only ensure even thickness, but will also reduce the prep time. If you don’t have a mandoline a very sharp knife is the next best thing we recommend.

FAQs

Why do I bake this dish covered first, then uncover it?

Covering this dish in the beginning will allow the vegetables to soften without drying the dish out. Once the vegetables get to a good point, uncovering them will allow the top of the gratin brown and crisp up, while allowing some of the excess liquid to thicken/evaporate.

Can I prep this dish ahead of time?

Yes! This dish can be made up to a day ahead of time and refrigerated, tightly wrapped in foil. When ready to bake, just place the covered gratin in the oven, adding about an extra 5-7 minutes of baking time to the dish (covered).

Just know that if you prep this dish ahead of time, you run the risk of the beets bleeding from sitting in the cream. This won’t effect the flavor at all, but it’ll change the look of this dish.

I didn’t make the cheesy root vegetable gratin ahead of time and my beets still bled. Why?

The culprit was most likely the amount of cream/liquid used. We made sure to scale back on the amount of cream used to toss with the beets as well as the cream that sits in the bottom of the baking dish.

You really want to make sure the sliced beets are just barely coated in liquid to ensure they don’t dry out while baking. You also want to make sure the bottom layer of your baking dish is just coated with a thin layer of cream and sprinkled with Parmesan. The amount of cream used may vary just a little bit, depending on the surface area of the baking dish you’re using, so it’s best to eyeball this.

Why are there ranges for the number of each vegetable to use?

We add a small range for each vegetable because not all 3 quart baking dishes are oval and we encourage you to use what you have on hand (which would change the amount of surface area there is).

This plus the fact that the thickness of the sliced vegetables, the size of each vegetable themselves, and the degree of the bias in which the sliced vegetables are placed into the baking dish will all vary slightly from person to person, effecting the number of vegetables needed.

If there is a range from the number of vegetables to use, how did you calculate the nutrition facts?

The nutrition facts are based on the lowest number vegetables in each range in the ingredient list.

A close up of cheesy root vegetable gratin with a spoon.

Variations for Cheesy Root Vegetable Gratin

Chives, green onion, sage, and rosemary or a combination of herbs make a great alternative to the fresh thyme.
Shredded fontina, Swiss, comté, gouda, and mild cheddar cheese all make great cheese alternatives for gruyere.
Whole milk or half and half can be used in place of cream, although there will be more liquid pooled in the bottom of the gratin after it’s baked.
Turnips and rutabaga make great root vegetable alternatives for any of the three used in this recipe.

What to Serve with Our Cheesy Root Vegetable Gratin

If you’re looking for other delicious thanksgiving or holiday side dishes, you can head on over to our Holiday Headquarters for some of our favorite ones! Enjoy!