Baking Bulbs: Celeriac Gratin with Thyme and Gruyere

Are you planning a Thanksgiving menu? This week we’ll be suggesting a few of the feast-worthy garden-to-table recipes from the past year:

Before we reach a point when it’s acceptable to light the furnaces and really hunker down for winter, I like to cook things that at the very least require the use of the oven. Truth is, after a summer spent avoiding it, I’m more than ready to fire up the beast and bake my way to an acceptance that warm weather is behind us.

My go-to comfort food in the fall is a cheesy, decadent gratin. Thinly sliced root vegetables–turnips, parsnips, potatoes, even rutabagas are all good choices–turn into velvety discs underneath all that cream and cheese. Celeriac, which is something of the ugly duckling of the root vegetables, lends its own delicious celery-flavored notes to the dish.

If you tackle one new vegetable this season, make it celeriac, and enjoy it in a gratin. See below for an ingredients list and step-by-step instructions:

Photography by Erin Boyle.

Above: The finished dish, richly golden and ready to enjoy.

Above: Celeriac gets overlooked because it’s ugly and perplexing, at the same time. But treated like any other root vegetable, it can be roasted, mashed, and baked to rib-sticking perfection.

Above: The original recipe called for turkey or chicken stock, but I substituted a rich vegetable broth instead. Cooking the celeriac in the broth prior to baking gives it a rich flavor and ensures that the root vegetable won’t be tough or stringy after baking.

Above: A thick, tough skin makes peeling celeriac seem daunting, but armed with a sharp knife, you can remove the outer layer quite quickly.

Above: After simmering the celeriac, I sliced it into 1/4-inch morsels and layered them in an oval baking dish.

Above: The cooking liquid, seasoned with mustard, salt, and pepper, drowns the layered celeriac.

Above: Topped with a healthy layer of cheese, the gratin is ready for the oven.

Celeriac Gratin with Thyme and Gruyere

Adapted from the Regina Schrambling’s recipe in the LA Times.

Ingredients:

• 1 cup vegetable broth
• 2 cups heavy cream
• 2 large celery roots (celeriac bulbs)
• 2 tablespoons whole-grain Dijon mustard
• 1 teaspoon sea salt
• Freshly ground pepper, to taste
• 1 teaspoon fresh thyme leaves
• 1 cup finely grated Gruyere cheese

Instructions:

In a large pot, bring vegetable broth and cream to a simmer. Trim the ends of your celeriac and use a sharp knife to peel the bulb. (Don’t bother with a vegetable peeler, the tough skin needs something sharper.) When the bulbs are peeled, quarter each bulb, lengthwise. Add celeriac to the pot of simmering liquid. Cover and cook, turning occasionally, until the celeriac is tender (about 30 mins).

Heat oven to 350 degrees.  Remove pot from heat. Use a slotted spoon to transfer celeriac pieces to a large cutting board. When cool enough to handle, slice the celeriac into 1/4-inch-thick slices.

Layer the sliced celeriac in the bottom of an ungreased baking dish. Worry some over creating a pretty design, but not too much. Sprinkle with fresh thyme leaves. Bring the liquid remaining in the pot to a boil (watching carefully to make sure it doesn’t boil over). As the liquid thickens, add mustard, salt, and pepper to taste. Pour the mixture over the layered celeriac, covering completely (if it looks soupy, all the better). Sprinkle the cheese evenly over the top, covering completely. Garnish with a sprig or two of thyme and bake for from 35 to 40 minutes, until the liquid is burbling and the cheese has turned richly golden-brown. Serve hot, preferably in front of a roaring fire.

Would you like us to send you a new recipe every Friday? Subscribe to our Gardenista Daily email.  For more of our favorite dinners, see our complete list of Garden-to-Table Recipes.

Getting ready for Thanksgiving? See all our Holiday Prep tips for entertaining.

Finally, get more ideas on how to successfully plant, grow, and care for thyme with our Thyme: A Field Guide.

Interested in other edible plants for your garden? Get more ideas on how to plant, grow, and care for various edible plants (including flowers, herbs and vegetables) with our Edible Plants: A Field Guide.

N.B. This is an update of a post that originally published on October 11, 2013.