I have to admit, I’ve walked by piles of celery root both in the grocery store and at the farmers market many times and thought, there had to have been a couple of characters in Lord of the Rings inspired by those things, at least visually… That said, I’ve just as often thought, I’ve got to try using celery root in place of potatoes to make ‘Mashed Potatoes’. I’ve heard about this substitute both because it’s a less starchy version of this favorite holiday side, and presumably because it’s really tasty. With celery root being in full season now, I at last stopped to actually buy, not just photograph, a few bulbs to try this fabled dish. Well guess what, it’s excellent! And like traditional mashed potatoes, making them is pretty darn easy.
In this recipe, I added a roasting step to amp up the taste intensity. We’re having this with turkey breast, which is a little mild, and I wanted the celery root to almost act as a gravy, flavoring wise. The flavor yielded by roasting would also allow this dish to stand up to steak or roasted lamb.
Hands-on time is about 45 minutes total including clean up, and this recipe makes 4-6 servings. These re-heat easily and will last in the fridge for 4-5 days. More on reheating once we get through the steps.
– 2 Lbs Celery Root (Pre-Peel), about 3 bulbs
– 4 Large Fingerling Potatoes
– Two Tablespoons Olive Oil
– 1 Teaspoon Salt
– 1/2 Cup Chicken Stock
– 1/2 Cup 1% Milk
– 1/4 Cup Water
– 2 Tbsp Butter, Melted
– 1 & 1/2 Tsp Fresh Thyme, Chopped
Preheat the oven to 400 Degrees F.
Prepare a roasting pan by lining with parchment paper.
Set a food processor out.
Set up the butter in saucepan on the stove top for melting during Phase 2.
Phase 1: Pre-Roast:
– First using a sharp knife, then a vegetable peeler, remove the tough skin and dirt from the Celery Root. I used a knife for the more gnarly part, then a vegetable peeler for the rest.
– Also peel the potatoes. For reference, the fingerlings I used are below. If you don’t happen to find larger fingerlings such as these, do still use the fingerling variety, simply add a few more.
– Cut the peeled celery root and the potatoes into about one-inch cubes and place in a mixing bowl.
– Add olive oil and toss to coat.
– Sprinkle salt evenly over and toss once more.
– Spread the mixture out on your prepped roasting pan and roast at 400 Degrees F for 40 minutes.
Phase 2: Post Roast:
– Begin melting the butter over low heat on the stovetop.
– Set the roasting pan on a cooling rack and transfer the roasted celery root and potatoes into a food processor.
– Pulse enough times to throughly chop all of the pieces, about 20 five second pulses.
– Add the melted butter, chicken stock, milk and water and mix until smooth, about 2-3 minutes, longer if necessary.
– Transfer the mash to a mixing bowl and *then* add the chopped thyme. Stir with a spoon to throughly incorporate.
Serve with a garnish of whole thyme and enjoy this super tasty late-Fall side with your favorite protein!
Note about reheating – the oven or the stovetop works (if the mash starts to seem dried out during reheating, simply add up to a tablespoon of milk, little by little to regain desired consistency) but over Thanksgiving I learned a new way to reheat all things mashed. It’s via a sous vide of sorts, aka a hot water bath: Put a large pot of water on the stove and heat as if to boil. Then, place the Mashed Celery Root & Potatoes into the appropriate sized zip-lock bag and seal, removing most of the air. When the water is quite warm, *not* boiling, dunk the bag into the water and hold for 10 seconds. Remove the bag and wearing gloves or handling with a kitchen towel, massage to move the heated parts around. Repeat 2-3 times. Then, simply cut one corner of the bag, and squeeze from the top down to serve onto your plate or serving bowl. (A huge shout-out to Kenji over at Serious Eats for this reheating technique!) Yes, any guests you may happen to have around may raise an eyebrow when they see mashed root vegetables in a ziplock bag, but it’s worth it. The reheating results are better because of even heat distribution without drying, and the clean up is actually much easier!