These French Mashed Potatoes Feel So Sophisticated (but Couldn’t Be Easier)

published Nov 23, 2021
christmas
French Celery Root Mashed Potatoes

These celery root mashed potatoes, with their slightly sweet and earthy flavor, strike a sophisticated note among all the other (rather heavy) dishes on the Thanksgiving table.

Serves4 to 6

Makes4 cups

Prep25 minutes

Cook30 minutes

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Credit: Ivy Manning

I’ve been making celery root mashed potatoes for Thanksgiving since I was 14 years old. I got the recipe from a French women’s magazine that my sister sent to me from her year abroad at the Sorbonne. As a young Francophile studying French, that magazine was a worldly treasure. I pored over every page, obsessing over details like how Parisian women tied their silk scarves — and how they cooked chic recipes.

Enter: the recipe for celery root mashed potatoes, which has endured for decades in my family. They strike a sophisticated, continental note among all the other (rather heavy) dishes on our Thanksgiving table. A guest once remarked that they loved the “green taste” of our mashers, and somehow the name stuck — we’ve been calling them “green potatoes” ever since. In all honesty, though, I’d describe the flavor of the celery root in the dish as slightly sweet and earthy, not green. A bit like parsley stems, but more buttery.

Credit: Ivy Manning

What Is Celery Root?

If you’re unfamiliar, celery root is a knobby root vegetable that looks something like a dirty softball with roots sprouting out the base. They appear from fall to early spring in well- stocked grocery stores and farmers markets, with the freshest specimens sporting a few puny celery-like stalks still attached to the top. Choose a root that has no mushy spots and is heavy for its size. Once you’ve trimmed the gnarliest roots off the celery root, peel the rest of the thin skin with a vegetable peeler to keep waste to a minimum. 

Credit: Ivy Manning

Making Celery Root Mashed Potatoes

Because celery root is denser than potatoes, I cut them into thin matchsticks about 1/4- to 1/2-inch thick while keeping the potatoes in rather large (3-inch) chunks or quarters so everything cooks evenly. A bay leaf and garlic cloves are added to the cooking water with a good amount of salt to season the cooking liquid, some of which you’ll reserve and use later to loosen the mash in lieu of milk or cream.

I used to run the cooked veg through a food mill as the French magazine instructed, but these days I prefer them with a bit more texture, so I mash them with a good ol’ potato masher. Then I stir in the reserved cooking liquid, just a few tablespoons at a time, until the mixture is loose and silky. To amplify the flavor of the celery root, the recipe is finished with freshly grated nutmeg and a few pinches of cayenne pepper, a classic French combo that is used to finish cream sauces and gratins. This little detail makes the mash taste trés chic, so don’t skip it!

Prepping Ahead

The finished dish can be made up to a few days in advance and refrigerated, which makes it a real boon when I’m wrestling a turkey or roast and multiple side dishes, plus entertaining guests. To reheat, I scoop them into a small (4- to 5-quart) slow cooker (I rub the crock with butter first) and cook them on low heat until they’re hot in the middle, 3 to 4 hours. They can be held on “keep warm” for an hour or two, if you can wait that long.

French Celery Root Mashed Potatoes

These celery root mashed potatoes, with their slightly sweet and earthy flavor, strike a sophisticated note among all the other (rather heavy) dishes on the Thanksgiving table.

Prep time 25 minutes

Cook time 30 minutes

Makes 4 cups

Serves 4 to 6

Nutritional Info

Ingredients

  • 2 quarts

    (8 cups) cold water

  • 1

    medium celery root (about 1 pound)

  • 1 1/2 pounds

    Yukon Gold potatoes (3 large, or 5 to 6 medium)

  • 3 peeled cloves

    garlic

  • 2 tablespoons

    kosher salt, plus more for seasoning

  • 1

    bay leaf

  • 5 tablespoons

    unsalted butter

  • 1/4 to 1/2 teaspoon

    freshly grated nutmeg

  • 1 pinch

    cayenne pepper, plus more as needed

Instructions

  1. Place 2 quarts cold water in a large pot.

  2. Trim the top stalks (if present) and bottom roots from 1 medium celery root. Peel the remaining skin from the celery root with a vegetable peeler or sharp knife. Halve the celery root, then cut crosswise into 1/3-inch-thick slices. Stacking a few slices at a time, cut lengthwise into 1/2-inch-wide matchsticks, adding them to the pot of cold water as they are cut to prevent them from turning brown.

  3. Peel 1 1/2 pounds Yukon Gold potatoes, cut into 3-inch chunks, and add to the pot. Add 3 peeled garlic cloves, 2 tablespoons kosher salt, and 1 bay leaf to the pot. Bring to a boil over high heat. Reduce the heat to medium-high and simmer, stirring occasionally, until a paring knife goes easily into the potatoes and the celery root is tender, 10 to 15 minutes. Meanwhile, place a heatproof colander in the sink. Place 5 tablespoons unsalted butter in a small microwave-safe bowl and microwave until melted, about 40 seconds. (Alternatively, melt the butter on the stovetop.)

  4. When the vegetables are ready, scoop out 1 cup of the cooking liquid. Drain the vegetables through the colander and let sit for a minute to let some of the steam dissipate. Discard the bay leaf, then pass the vegetables through a food mill back into the pot, or return the vegetables to the pot and mash with a potato masher until smooth. (Do not use a ricer, which will not break down the celery root very well.)

  5. Add the melted butter and stir to combine. Stir in the reserved cooking liquid a little at a time to achieve a loose, creamy mash (about 1/2 to 3/4 cup). Season with 1/4 to 1/2 teaspoon freshly grated nutmeg and a pinch of cayenne pepper. Taste and season with more kosher salt and cayenne if desired.

Recipe Notes

Buying celery root: Look for a very firm celery root that feels heavy for its size. The less gnarly it is, the easier it will be to peel.

Vegan: To make the dish vegan, substitute melted vegan butter (I like Earth Balance Vegan Buttery Sticks) for the butter.

Make ahead: The mashed potatoes can be made up to 2 days in advance, cooled completely, and refrigerated in an airtight container. To reheat, scoop them into a small buttered slow cooker, cover, and cook on LOW until heated through, 3 to 4 hours. Alternatively, microwave in a microwave-safe serving dish on high, stirring occasionally, until heated through, about 3 minutes.

Storage: Leftovers can be refrigerated in an airtight container for up to 4 days.