Ingredient

Celeriac

Celeriac is a knobbly, hairy, soil-caked root that looks like something dug up rather than grown, and it is one of the most useful winter vegetables there is. It tastes of celery crossed with a nutty, faintly sweet root, and it does two things — purée and rémoulade — better than anything else in the vegetable rack.

How to get into one

The peeling is the barrier, and a peeler is the wrong tool.

1. Cut a flat slice off the top and the bottom, so the root stands upright and stable on the board.
2. Take a knife — not a peeler — and cut down the sides in strips, following the curve, removing the skin and the tangle of rootlets at the base together. The bottom is a mass of fibrous roots and dirt and there is nothing to salvage there.
3. Trim any remaining brown patches or hollow spots. Some waste is unavoidable; a fifth of the weight is normal.
4. Put the peeled flesh straight into water with lemon juice or vinegar in it. Celeriac browns quickly once cut, faster than a potato.
5. Cut it into whatever shape the dish wants — it is dense and does not fall apart, so chunks, batons and fine julienne all hold.

What it is genuinely best at

• Purée. Simmered in milk or stock until soft, then blended with butter. Silkier and far more interesting than mashed potato, and the classic partner for scallops, game and pork.
• Rémoulade. Raw, cut into fine matchsticks, dressed with mustardy mayonnaise, lemon and parsley. A French bistro staple and the best raw use of any root vegetable.
• Roasted in wedges, which brings out real sweetness and crisps the edges.
• Mashed with potato, half and half, which lightens the mash and adds flavour without losing the familiar texture.
• In a gratin, sliced thin with cream and thyme, alone or layered with potato.
• Salt-baked whole. Encased in a salt crust and baked for an hour or more, it steams in its own moisture and comes out concentrated and remarkable. A restaurant technique that works at home.
• In soup, with apple, which is a natural pairing — the acidity and sweetness are exactly what it wants.
• Chips or crisps, cut thin and fried. Lower in starch than potato so they crisp differently, more like a root vegetable crisp.

Buying and keeping

Size

Medium is better than enormous. Very large celeriac can be woody or hollow in the middle.

Weight

It should feel heavy for its size. Light means it has dried out.

Firmness

Hard all over. Soft patches mean rot underneath.

The top

If the stalk end is soft or hollow-sounding, the middle may be spongy.

Storage

Weeks in the fridge or a cool place, unwrapped or loosely wrapped. It is a genuinely long-keeping vegetable.

Once cut

Wrap the cut face and use within a few days, or keep the pieces in acidulated water.

What it tastes like, and what it goes with

Celery, but rounder and less aggressive, over a nutty, mildly sweet, faintly earthy base. It is far less watery than celery and much more substantial — it behaves like a root rather than a stalk, which it is.

It pairs naturally with things that are either fatty or sharp. Cream, butter and milk are the obvious ones, because purée is what it is best at. Apple, lemon and mustard work on the other side, cutting through. Walnut and hazelnut echo the nuttiness. Pork, game, duck and scallops are the traditional protein partners, and truffle is the luxury one.

It also takes a surprising amount of black pepper and thyme, and it is one of the few vegetables that genuinely benefits from nutmeg.

Common questions