With its wrinkled, whitish skin and protruding stringy roots, celeriac - also known as celery root, knob celery, and turnip-rooted celery - won't win a beauty contest. The off-putting appearance makes most customers walk right by it. European cooks prize the knob, which is good raw or cooked. It's been popular since the 17th century, especially in France, one of the major growers.
Celeriac is a variety of branch celery, cultivated exclusively for its turnip-like root. It tastes like a combination of parsley and celery. A cousin to carrot, parsnip, and parsley, this hearty vegetable is typically harvested now and stores well for months. Unlike stalks of celery, which are stringy, celeriac has a texture more like a potato, but without the starch. Celeriac can be grated into a salad, like in the classic French celeri remoulade, in which the root is blanched, then dressed in a mustardy mayonnaise sauce. But you can also mash it, glaze it, puree it into a soup, or slice it into a gratin to serve with roast meats.
When buying the vegetable, if you have a choice, select one with its green leaves still attached. Avoid large knobs, which tend to be spongy and fibrous at the core. The best are small and heavy (about the size of an apple), very white, without soft or brown spots. The thick warty skin and roots must be peeled, and you end up discarding at least a quarter of the vegetable. Because it releases an enzyme once cut, celeriac has to be dropped into a bowl of water mixed with a few drops of lemon juice or vinegar to keep from turning brown. Uncut knobs can be stored in the fridge for one to two weeks, well wrapped in a paper bag.
"It is fairly easy to find celeriac, although not locally grown," says Tony Casieri, produce manager for Wilson Farms in Lexington. "Most of our celery roots come either from Canada or Holland. We also sometimes get our supplies from the West Coast where most celeries are grown." Casieri says that customers who buy celeriac at the farm stand are already familiar with it.
At Petit Robert Bistro, chef and owner Jacky Robert serves savory classics such as the popular remoulade, or mashes or fries the root. It also appears in desserts, such as a sweet celeriac soup with apples. "I first puree cooked celeriac, then I mix it with a creme Anglaise," he says. "In fact, most chefs interested in creative cuisine will love to use celeriac." If they know it, they know enough to embrace it. - BÉATRICE PELTRE