I have to tell you about a fan-freaking-tastic dish I’ve been making recently: Parsnip Gratin with Gruyère and Thyme Recipe. It’s creamy, cheesy, and packed with that earthy sweetness from parsnips, all perfectly accented by fresh thyme and nutmeg. If you’ve been looking for a cozy, impressive side that will wow your family or guests, you’re in the right place—this recipe never disappoints!

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Why You’ll Love This Recipe

Comfort Food with a Twist: Parsnips give a sweet, nutty flavor that’s more interesting than your average potato gratin.
Rich yet Elegant: Gruyère melts beautifully, creating a creamy texture that’s just right—not greasy or heavy.
Herby Freshness: The thyme and nutmeg elevate the dish with subtle herbal and warming notes.
Make-Ahead Friendly: You can prep it in advance and pop it back in the oven, making mealtime stress-free.

The image shows a white plate with a small serving of scalloped potatoes arranged in three visible layers. Each layer is composed of thin, slightly browned potato slices with a creamy sauce between them, giving a soft texture. The top layer is golden with melted cheese and small green herb sprigs scattered, likely thyme, adding a touch of freshness. The plate rests on a white marbled surface with a white cloth underneath, and in the background, a dark baking dish is blurred out, hinting at more scalloped potatoes inside. A silver fork lies next to the potatoes on the plate. Photo taken with an iphone --ar 4:5 --v 7

Ingredients You’ll Need

These ingredients come together in harmony—the parsnips’ natural sweetness, the smooth cream, and the nutty Gruyère, all brightened up by thyme’s fresh notes. Here’s what you’ll want to grab at the store.

Parsnips: Look for firm, fresh parsnips without blemishes; thinner ones slice more evenly.
Onion (yellow or white): Adds a subtle sweetness—choose a medium-sized, firm onion.
Heavy whipping cream: Don’t swap for milk or half and half here; the richness really makes this gratin sing.
Butter: For greasing the pan, which helps the gratin slide out easily and adds flavor.
Fresh nutmeg or ground nutmeg: Just a touch adds remarkable warmth and depth.
White pepper: Milder than black pepper, it blends smoothly without dark specks.
Kosher salt: The perfect seasoning layer for flavor balance.
Fresh thyme: Fresh is best here; it gives a bright, fragrant punch.
Flour or rice flour: This helps thicken the cream sauce gently, keeping things silky.
Garlic cloves: Minced fresh garlic amps up the flavor without overpowering.
Gruyère cheese: You want a good-quality grating cheese for that perfect melt and nuttiness.

Note: You’ll find the complete list of ingredients, along with their exact measurements, in the printable recipe card at the bottom of this post.

Variations

I love that this Parsnip Gratin with Gruyère and Thyme Recipe is so versatile. I often tweak it just a little depending on what’s on hand or my mood. Feel free to make it your own!

Herb swaps: I sometimes swap thyme for rosemary or sage, which changes up the vibe deliciously.
Dairy-free version: Use a plant-based cream and a vegan melting cheese alternative if you prefer dairy-free; it’s not quite the same, but still tasty.
Add a crust: Sprinkle panko breadcrumbs on top for a crunchy, golden crust if you like added texture.
Spice it up: A pinch of cayenne or smoked paprika gives a subtle kick without overpowering the gratin’s mellow flavors.

How to Make Parsnip Gratin with Gruyère and Thyme Recipe

Step 1: Prep and Slice Like a Pro

First up, preheat your oven to 400°F. Peel those parsnips, then slice them super thin—about 1/8 inch if you can. I swear by my mandolin here; it makes the slices even and the gratin cooks perfectly every time. If you don’t have one, just do your best with a sharp knife and take your time—it’s worth it! Also, slice your onion thinly and grate the Gruyère so everything is ready to go.

Step 2: Layer With Love

Butter a 9×13-inch baking dish generously—this little step is key to prevent sticking and adds subtle richness. I always put a sheet pan on the oven’s lower rack to catch any bubbling cream overflow; it’s a mess-saver! Then, layer the parsnips and onions, adding 2/3 of the cheese and 2/3 of the thyme in between layers. Save the prettiest parsnip slices for the top so it looks amazing when it’s done.

Step 3: Make the Creamy Herb Sauce

In a saucepan, gently heat your heavy cream with salt, white pepper, nutmeg, flour, garlic, and the last bit of thyme. When it starts to simmer, pour it carefully over the layered parsnips in the dish, tilting it so the cream seeps into every nook and cranny. The flour helps thicken the sauce just enough, and the garlic gives a wonderful gentle flavor. Sprinkle the rest of the cheese, thyme leaves, and a little extra nutmeg on top.

Step 4: Bake, Cover, and Uncover

Cover the dish tightly with parchment paper and foil to seal in the moisture. Bake it on the middle rack for 45 to 60 minutes, until the parsnips are fork-tender—thinner slices will cook faster, so keep an eye on it. Don’t worry if it looks watery; that’s normal and will set as it cooks. Once tender, remove the foil and bake uncovered for about 15 minutes until golden and bubbly on top. This step adds that irresistible cheesy crust.

Step 5: Let It Rest

Here’s a trick I learned: let your gratin rest at room temperature for 15-20 minutes before serving. This waiting time is magic for the sauce to thicken and settle, making every bite smooth and luscious without being runny.

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Pro Tips for Making Parsnip Gratin with Gruyère and Thyme Recipe

Mandolin Mastery: Using a mandolin for slicing parsnips not only speeds things up but ensures even cooking—no thick chunks left behind!
Cream Consistency: Stick to heavy cream for that silky texture; swapping milk or half and half makes the gratin runny and less flavorful.
Cover Well to Keep Moisture: Don’t skip sealing with parchment plus foil—that steam trap is what makes your parsnips tender but not dried out.
Rest Before Serving: Resist the urge to dig in immediately; letting it rest helps the sauce thicken, giving you that perfect spoonful.

How to Serve Parsnip Gratin with Gruyère and Thyme Recipe

A close-up of a black pan filled with a baked dish showing about three visible layers of thin, creamy white potato slices, some browned edges and melted cheese on top, with green sprigs of fresh thyme scattered on the golden surface. The pan is on top of a white cloth on a white marbled textured background. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

I like to scatter a few fresh thyme leaves on top right before serving for that fresh herbal aroma and a pop of green. Sometimes a light dusting of freshly grated nutmeg adds a cozy, aromatic touch that guests always notice and compliment.

Side Dishes

This gratin pairs beautifully with roast chicken or a juicy pork tenderloin. For a vegetarian meal, I like serving it alongside a crisp green salad or sautéed green beans for a balanced plate that feels special but not fussy.

Creative Ways to Present

For holiday dinners, I’ve served this gratin in individual ramekins—everyone gets a personal cheesy, creamy parcel that feels extra indulgent. You can also sprinkle toasted walnuts or breadcrumbs on top for a delightful crunchy contrast that surprises and delights.

Make Ahead and Storage

Storing Leftovers

After it cools completely, I cover the gratin tightly with foil or plastic wrap and store it in the fridge for up to 3 days. It reheats beautifully without losing its creamy texture.

Freezing

I’ve frozen this gratin a few times in an airtight container before baking. When you’re ready to enjoy, thaw overnight in the fridge then bake as usual—just add a few extra minutes if needed. The flavors stay intact, and it’s a great make-ahead option.

Reheating

Reheat leftovers in a 350°F oven, covered with foil to prevent drying out, for about 20-25 minutes until warmed through. Then, remove foil and bake 5-10 more minutes to regain that bubbly golden top. Microwave works in a pinch but the oven is best for texture.

FAQs

Can I substitute potatoes for parsnips in this gratin?

You can, but the flavor and sweetness will change. Parsnips have a unique nutty, sweet taste that potatoes lack. If you use potatoes, you might want to adjust seasoning and expect a different texture. This recipe shines with parsnips.
Why do I need to cover the gratin while baking initially?

Covering traps steam, which helps cook the parsnips through and keeps the dish from drying out. Removing the cover at the end allows the top to brown and get that lovely golden crust.
Can I make this gratin vegan?

Yes, but you’ll need to substitute heavy cream with a rich plant-based cream and use a vegan cheese that melts well. The result won’t be identical but can still be creamy and satisfying with the right ingredients.
How thin should the parsnip slices be?

About 1/8 of an inch is ideal—it ensures even baking and tenderness. Thicker slices will take longer to cook and might result in a less creamy texture.
Can I prepare this dish ahead of time?

Absolutely! You can assemble it, cover tightly, and refrigerate for up to a day before baking. Just add extra baking time if it comes straight from the fridge.

Final Thoughts

I absolutely love how this Parsnip Gratin with Gruyère and Thyme Recipe turns out every time—the layers of creamy, cheesy goodness with those sweet, tender parsnips always impress. It’s become a staple during holidays and special dinners, and my family goes crazy for it. I hope you’ll give it a try and find it as comforting and delicious as I do. Once you nail this recipe, it might just become your go-to side dish too!