Celery root, also known as celeriac or knob celery, is one of those vegetables that confounds many people. What is it? Is it really the root of the celery plant? What do you do with it? What does it taste like?

Celery root is related to celery, but it’s a different variety. Whereas celery is cultivated for its stalks and leaves, celeriac is cultivated for the root. Its flavor is definitely celery-like, only deeper and earthier. It’s kind of off-putting in its appearance—big, bulbous, knobby, and usually dirt-encrusted—and is not used as commonly as other root vegetables. But like so many overlooked vegetables, it’s rising in popularity.

As to what you can do with it, many things. You roast them, saute them, gratinee them, use them in soups and stews, and, as in this recipe below, puree them for a smooth, silky bisque.

Celery root bisque is often thickened with potatoes, but I’ve chosen instead to use oats, a trick I learned in culinary school. Oats not only increases the soups nutrition factor, but also makes it less starchy.

Speaking of nutrition, celery root contains vitamin C, vitamin K,  vitamin B-6, potassium, phosphorus, and fiber. It’s been shown to be beneficial for bone health, heart health, and lowering the risk of diabetes.

Enjoy!

Celery Root Bisque with Oats

Makes 6 to 8 servings.

2 large celery root knobs
2 tablespoons olive oil
4 cups chopped celery
½ cup chopped shallots
1 tablespoon kosher salt
5 cups vegetable broth
1/3 cup rolled oats
½ cup parsley*
2 tablespoons fresh thyme*
Freshly ground pepper to taste

*Don’t worry about chopping the herbs or if you have some stems. They’re going to be pureed.

Peel the celery root with a knife or vegetable peeler. Cut up the roots into cubes (you should get about 10 cups). Heat the oil in a large soup pot or Dutch oven. Add the celery and shallots and ½ teaspoon of the salt and sauté until softened, about 5 or 6 minutes.Add the celery root and 1 teaspoon salt and stir. Pour in the broth and add oats. Bring to a boil; lower the heat to medium-low, and simmer, covered, until the celery root is tender, about 40 minutes. Stir occasionally.Stir in the parsley and thyme and remaining salt.Transfer the soup in batches to a blender and puree until smooth. Pour each batch into a bowl. When all the batches are in the bowl, stir it to blend. Add pepper and stir. Taste the soup for seasoning and add more salt and pepper, if desired.If you’ve made the soup ahead of time, pour it back into the pot and heat gently over medium-low heat before serving.

Keep it stored covered in the refrigerator up to 5 days.