Farmer’s Market Celery Root Soup
When I shop at farmer’s markets, I like to let the produce drive at least some of my meals for the upcoming week. Farmer’s market day is especially important to me in the spring and summer since I live in New England where their fleeting bounty needs to be savored and optimized. In winter, I still love the rush that is market day, but it’s a more relaxed affair. I think the Winter markets have their own charms and I like to embrace the stability of winter market staples and lean into the cozy, comfy things you can cook with them.
My favorite way to cook many winter vegetables is as a smooth, thick soup. Soup is easy, approachable, and delicious! It’s the sort of meal that can be built from ingredients that can be found at my local farmer’s markets and keep the supporting ingredients limited to common staples. This is the kind of recipe that is a great answer to that realization of ‘shoot, I bought this beautiful [insert root vegetable or winter squash here] and don’t know what to make’ panic.
The bones of this recipe - caramelize an allium and winter root or squash of choice, deglaze and simmer with stock, puree and serve - is something I’ve been doing for years. It’s a process built from my favorite butternut squash soup published in Cook’s Illustrated at least 10 years ago (I went back to find the magazine and it’s actually only been 9 years; Cook’s Illustrated October 2011, Number 112, page 15). Since making the original I’ve riffed off it’s basic structure because
1) it was not an overly sweet recipe (squash soups especially can run sweet)
and
2) it was creamy and smooth without the addition of cream
The key part I’ve held onto all these years is the importance of creating a good fond. Fond is French for ‘base’ referring to the browned and caramelized bits that form on the bottom of the pan and is the flavor base for many a delicious soup, stock, or sauce. Over the years I’ve focused more on caramelizing my onions and then browning the vegetables as part of the fond, but you will always be rewarded for your patience to build fond.
While I’ve used the basics of this recipe to make many different soups over the years, I wanted to use it to highlight one of my favorite root vegetables that I feel often gets overlooked: celery root aka celeriac. You’ve probably seen it, even if you didn’t know what it was. It’s a gnarly looking vegetable that looks intimidating but is actually quite easy to work with!
I could be wrong, but I have the impression that celery has a bit of a bad rep in the larger world of eaters. It’s got a strong personality, stringy texture, and sadly is relegated as ‘rabbit’ food. I’ll admit, celery can be a bit overwhelming on its own. But I love it in Thanksgiving stuffing; I can’t imagine stock without it; and I like the occasional ‘ants on a log’ snack even though I’m 33. Unlike the spry celery stocks, the root has a meaty, supple texture that when roasted, simmered or sauteed has a more mellow earthy flavor while carrying the herbaceous elements of celery.
While I love celery root, it’s earthy flavor needs a bit of a lift, both with sweetness and acid. Apple and apple cider vinegar pair perfectly with celery root and you can get your apples from the farmer’s market for much of the winter season. I recommend something tart like granny smith, but even a milder, sweeter apple will produce good results.
For your stock, a homemade one is always ideal, but when I don’t have one on hand or forget to pull it from my freezer before hand, I’m a fan of using Better than Bouillon stock bases (this is not sponsored, I just love these products!). Stock bases are easy to use and keep for a long time in your fridge so it limits waste. I always have one of their poultry bases and the seasoned vegetable base in my refrigerator.
Lastly, if you want to up your soup game, go for garnishes! For texture, croutons made using a nice loaf from the farmer’s market is simple and lovely. It’s easier to cut a slightly stale loaf, but you can use a fresh one if your impatient like me. Just cut it up before you begin soup prep so the surfaces can dry out a bit, which will produce crispier croutons.
I really racked my brain for an additional element that would enhance the flavors in the soup without taking too much effort to make. Since receiving an Instant Pot as a wedding gift, I’ve been making Indian-ish dal using Priya Krishna’s handy Instant Pot dal chart. Through her and that chart I’ve learned about chhonk, butter or ghee infused with spices used as a finishing sauce, as a way to make dal more delicious. Seeing as I’m already relying on butter to add body to this recipe, I thought that browning it and infusing it with something would add another dimension without seeming out of place. That something ended up being lemon zest, which lifted and added a fresh note without adding more acid (of which the soup already had plenty). So, thank you Priya for inspiring this chhonk-like garnish!
4-6 servings
Time: 45 minutes
For the soup
3 tbsp butter, divided
1 sliced yellow onion (about 2 ½ cup)
1.5 lb celery root, chopped (about 4 cups)
1 granny smith apple, chopped (about 1 rounded cup)
Salt and pepper
1 tbsp apple cider vinegar
6 cups poultry broth or vegetable broth
For croutons
2-3 cups of cubed bread; sourdough or a rustic french loaf are nice
1 tbsp olive oil
Flaky kosher salt
For Lemon Infused Brown Butter
¼ cup butter
Zest of 1 lemon
Melt 2 tbsp of butter over medium heat in a large, heavy bottomed pot. Add Your onions and cook them until they are nicely caramelized. This will take 10-15 minutes. Resist the urge to stir them too much. If you find that spots are browning faster than other, occasionally deglaze the pan with a smidge of water (like a tbsp or less ) to distribute the color/flavor.
When onions are a nice golden caramel color, add the celery root and green apple and stir them to coat them in fat and onions. Season with salt and pepper. Again, resist the urge to stir too much to let the vegetables brown.
Once the apples and celery root are slightly softened and you’ve built a nice fond on the bottom of your pot, deglaze your pot with your apple cider vinegar. Scrape up all that tasty fond and cook for a minute more so the vinegar smell cooks off.
Add the stock and additional salt and black pepper if needed. Cover and turn up the heat and bring the pot to a boil. Once boiling, turn temp down to low and simmer covered for about 15 min, stirring occasionally.
If you’re making croutons, preheat your oven to 400F and toss your cubed bread with olive oil and salt. Toast your croutons until they are golden brown, 10-12 minutes.
Blend your soup until smooth using a blender or stick blender. If you are using a blender, let the soup cool slightly before blending to prevent it from exploding and making a mess.
Stir in your remaining tablespoon of butter until it is fully incorporated into the soup. Taste and adjust seasoning as needed.
If you are making Lemon Infused Brown Butter, melt your butter over medium low in a small pan or pot. Continue to toast the butter until the milk solids are golden brown and smell nutty, about 5 minutes. Remove the browned butter from the heat and add your zest; it will foam up quite a bit. Stir and pour the butter into a small bowl to cool it.
To serve, ladle the soup into bowls, drizzle with a generous amount of infused butter, and pile on the croutons.