Seriously, butter, cheese, cream. What’s not to love? Baked until golden brown and bubbly, this makes a lovely side dish for prime rib, ham, or other holiday roast.

Not Traditional but Utterly Delicious

I break from tradition a bit with this gratin, but the flavors work together beautifully. If you’re craving something new, interesting and delicious this is the recipe for you! Potatoes are probably the most familiar vegetable used in gratins, but for this, I lean into the root veggie’s sweet and earthy cousins: carrots and parsnips. A bit of fennel, with its delicate licorice notes, is also added to the mix. For the topping, chopped pecans replace commonly used breadcrumbs. The cheese sauce in this recipe is a béchamel enriched with sweet and earthy blue cheese, which technically makes it a Mornay sauce, but I’m a fan of alliteration, so blue cheese béchamel, it is.

How to Make Smooth Béchamel

Keep your béchamel lump free and silky smooth by warming up the milk and cream together in a separate pan, then slowly whisking the liquid into the butter and flour (a.k.a. roux) a little bit at a time so the flour and butter mixture can better absorb the liquid.Cooking the sauce over a steady medium to medium-low heat, along with stirring frequently, will help to prevent the béchamel from scorching.

When It Comes to Vegetables: Think Thin

A mandoline helps make quick work of the carrots and parsnips, giving you perfectly even and thin (about 1/8-inch) slices with every stroke. (Just be sure to watch your fingers and knuckles as you work!)However, if you don’t have a mandoline, don’t fret; a very sharp chef’s knife and a little patience will also do the trick.

Swaps and Substitutions

Don’t like blue cheese? Whisk in some grated Parmesan or Pecorino Romano instead. A smoked gouda could also be fun.You could even swap out the parsnips and carrots for different root vegetables; a combination of celery root and potatoes would be especially nice.

Make Ahead

I don’t recommend freezing the gratin, but to save time, you can assemble it unbaked the day before you plan to serve it. When you’re ready to bake, remove the gratin from the refrigerator, and let it sit for about 30 minutes to come to room temperature before popping in the oven.

More of Our Favorite Holiday Sides

Cheesy Spaghetti Squash Casserole Creamy Scalloped Potatoes Cauliflower Gratin Scalloped Potatoes with Caramelized Onions and Gruyere Brussels Sprouts Gratin

1 1/2 pounds parsnips, scrubbed and peeled 1 pound carrots 1 fennel bulb (about 8 ounces), trimmed 2 tablespoons unsalted butter, plus more for greasing 1/2 cup shallots, thinly sliced 1/2 teaspoon salt, plus more as needed 1/4 teaspoon freshly ground black pepper, plus more as needed 1 clove garlic, minced 2 teaspoons fresh thyme leaves, finely chopped

For the béchamel, and to finish:

2 cups whole milk 1 cup heavy cream 3 tablespoons unsalted butter 3 tablespoons (34g) all-purpose flour 3 ounces blue cheese, crumbled 1 teaspoon salt 1/2 teaspoon freshly ground black pepper 1/8 teaspoon freshly grated nutmeg Pinch ground cayenne pepper, optional 1 cup pecans, chopped

Top with half of the carrots, and season with another pinch of salt and grind of black pepper. Scatter half of the fennel mixture on top of the carrots. Repeat with the rest of the parsnips and carrots, finishing with the remaining fennel mixture. Set aside. In a small sauce pan set over medium-low heat, add the milk and cream. In a medium saucepan set over medium heat, add the butter. When the butter foams, whisk the flour into the melted butter, and cook until nutty smelling and light golden in color, about 3 minutes. Bring the béchamel to a simmer, keeping an eye on the heat and stirring frequently to prevent scorching. It will really start to thicken as it simmers. Reduce the heat to medium-low, and simmer until the sauce is thick and coats the back of a spoon, about 4 minutes. Scatter the pecans over the top of the gratin. (The gratin can be made ahead up to this point, then refrigerated until ready to bake.)