Celeriac, also called celery root, is the large round root of a variety of celery. Under its knobbly, earthy skin hides white flesh with a sweeter, more delicate celery scent.
It is underused but versatile: raw in matchsticks or marinated in salads, fried in strips, diced in soups with potatoes, cooked together with pasta. Peel it with a knife, as the skin is thick.