Winter Vegetable Gratin

I pulled this gratin out of the oven on a particularly bitter January night, and the kitchen filled with the smell of nutmeg and browned cheese. My partner wandered in from the living room, drawn by the scent, and we ended up eating it straight from the dish with two forks. It's the kind of recipe that turns a weeknight into something worth remembering.

The first time I made this for friends, I worried I'd sliced the vegetables unevenly, but no one seemed to notice. We sat around the table scraping the dish clean, talking late into the night while the snow piled up outside. That's when I realized this gratin wasn't just food, it was the thing that kept us all at the table a little longer.

Ingredients

• Potatoes: They anchor the dish with starch and help the layers hold together, I've learned that slicing them thin and even makes all the difference in texture.
• Butternut squash: Adds a subtle sweetness that balances the sharpness of the cheese, and it roasts into tender, golden ribbons.
• Parsnips and carrots: These root vegetables bring earthiness and a hint of natural sugar that caramelizes beautifully under the broiler.
• Leek: Mild and silky, it weaves through the layers with a gentle onion flavor that doesn't overpower.
• Garlic: Just two cloves, minced fine, give the whole dish a warm backbone without shouting.
• Whole milk and heavy cream: Together they create a sauce that's rich but not heavy, clinging to every slice of vegetable.
• Butter and flour: The base of the roux, whisked together until it smells faintly toasted and turns the palest gold.
• Dijon mustard: A teaspoon adds a quiet tang that wakes up the cream without tasting sharp.
• Nutmeg: Freshly grated if you have it, this spice makes the sauce smell like winter in the best possible way.
• Gruyère cheese: Nutty and melty, it's the soul of the gratin, I wouldn't swap it for anything else if I can help it.
• Parmesan cheese: A little goes a long way, adding salty depth and helping the top turn that perfect shade of amber.
• Breadcrumbs: They crisp up in the oven and give you something to crunch through before you hit the creamy layers below.
• Fresh thyme: Woody and aromatic, it ties the whole dish together with a whisper of herbaceousness.

Instructions

Prep your oven and dish:

Set the oven to 375°F and grease your baking dish generously. This step matters more than you'd think, it keeps the edges from sticking and makes cleanup so much easier.

Build the roux:

Melt the butter in a saucepan over medium heat, then whisk in the flour and let it bubble for a minute or two until it smells nutty. This is the foundation of a smooth, lump-free sauce.

Make the cream sauce:

Pour in the milk and cream slowly, whisking the whole time to keep it silky. Stir in the mustard, nutmeg, salt, and pepper, then cook until it thickens enough to coat the back of a spoon, about five minutes.

Fold in the cheese:

Take the pan off the heat and stir in half the Gruyère until it melts into the sauce. It should look glossy and smell like a French bistro.

Season the vegetables:

Toss all your sliced vegetables with the garlic, salt, pepper, and half the thyme in a big bowl. Get your hands in there if you need to, it's the best way to make sure everything is coated.

Layer the gratin:

Spread half the vegetables in the dish, pour over half the sauce, then repeat. Try to keep the layers somewhat even so everything cooks at the same rate.

Top and bake covered:

Scatter the remaining Gruyère, all the Parmesan, breadcrumbs, and thyme over the top. Cover loosely with foil and bake for 35 minutes until the vegetables start to soften.

Finish uncovered:

Pull off the foil and bake another 15 minutes until the top is golden and bubbling at the edges. Let it rest for 10 minutes before serving so the sauce can settle and the layers hold together when you scoop.

Pin This

One winter evening, I brought this gratin to a potluck and watched as people went back for seconds and thirds. Someone asked for the recipe, and I scribbled it on a napkin while we all stood around the kitchen island. That's when I knew it had earned its place in my rotation.

How to Slice Vegetables for Even Cooking

I use a mandoline for this now, but a sharp knife and patience work just as well. Aim for slices about an eighth of an inch thick, and try to keep them consistent so everything bakes at the same pace. If a few pieces are thicker, tuck them toward the bottom where they'll get more heat.

Choosing the Right Cheese

Gruyère is classic for a reason, it melts beautifully and has a nutty complexity that other cheeses don't quite match. If you can't find it, Emmental or a sharp white Cheddar will work, but the flavor will shift a little. I've tried it with mozzarella once, and it was bland, so I'd steer clear of that.

Storing and Reheating Leftovers

This gratin keeps in the fridge for up to four days, covered tightly. I reheat individual portions in the oven at 350°F for about 15 minutes, covered with foil so they don't dry out. The microwave works in a pinch, but you lose that crispy top.

• Add a splash of cream or milk before reheating if the sauce looks dry.
• Freeze portions in airtight containers for up to two months.
• Let frozen gratin thaw in the fridge overnight before reheating for the best texture.

Pin This

This gratin has become my go-to when the weather turns cold and I need something that feels like a hug on a plate. I hope it warms your table the way it's warmed mine.

Recipe FAQs

→ What vegetables are used in the gratin?

Potatoes, butternut squash, parsnips, carrots, and leek are thinly sliced and layered to create the foundation of the dish.

→ How is the creamy sauce prepared?

Butter and flour are cooked to form a roux, then milk, cream, Dijon mustard, and seasonings are whisked in and thickened before mixing with Gruyère cheese.

→ Can this dish be made gluten-free?

Yes, by using gluten-free flour and breadcrumbs, the gratin can be adapted to meet gluten-free dietary needs.

→ What cheeses are recommended for the topping?

Gruyère and Parmesan cheeses provide a flavorful, golden crust, but Cheddar or Emmental can be used as substitutes.

→ How long should the gratin be baked?

The gratin is baked covered for 35 minutes, then uncovered for 15 minutes until golden and tender, followed by a 10-minute resting period before serving.

→ Are there variations for dietary preferences?

For a vegan option, plant-based milk, cream, and cheese alternatives can be used while maintaining the dish's creamy texture.