Celeriac is a variety of celery cultivated for its large, thick, turnip-like root. The stalks and leaves, which look and smell like celery, are good for flavouring stocks. The celeriac flesh itself has a tough, fibrous texture, with a deliciously nutty celery flavour.
The season is very short for celeriac; it is only available in early winter, and frosts will damage the roots. Hard heavy roots indicate the celeriac is solid all the way through and has been freshly dug. The flavour is better from celeriac that has not been around too long.
To prepare, peel away the thick skin which is often gnarled with tiny roots. The insides are white and fresh, smelling like freshly cut celery hearts. Keep peeled, cut celeriac in acidulated water or it will oxidise and turn brown.
Celeriac is only found in recipes from the north of Italy, mostly used in soups.