Onions belong to the allium family, which also includes leeks, shallots, garlic and chives. In the early nineteenth century, onions were thought to be too strongly flavoured for delicate English dishes (as was garlic). Purists advocated boiling onions to tame its pungent flavour before using.

What to look for
When buying, look for firm, heavy onions with a dry wispy skin. If stored in a cool, dark and dry atmosphere, they'll keep for a couple of months. This does depend on the amount of moisture contained in an onion - the dryer and harder the onion, the longer it will keep.

Tear-jerking...
Although there's nothing whiffy about whole, unpeeled onions, once cut, they give off a volatile odour, which irritates the eyes. We haven't yet found a foolproof way of avoiding the 'streaming eyes' syndrome, although some people are convince that rinsing onions in cold water before chopping, or chewing piece of bread when cutting onions helps alleviate unpleasant symptoms.

Know your onions...

Brown onions
All-rounders, these onions are used in everyday cooking in Britain. Depending on when they're in-season, the flavour varies from mild through to eye-wateringly strong. Spanish onions tend to be bigger than many British varieties, and have a milder taste.

Red onions
Characterised by their reddish, almost mauve skin, red onions add a splash of colour to salads and salsas. In the Indian subcontinent they're as common as the brown onions in Britain. The flavour varies according to the variety and country of origin. Southern Italy produces particularly fine quality red onions.

White onions
Notable for its white skin, these onions are stronger on flavour than regular brown onions. More often used in spicy Mexican dishes than in British cooking, they're too pungent for most people to eat raw.

Shallots
Milder than onions, shallots are popular in French cooking and are noted their subtle flavour. Thai shallots, especially when fried, have a more pronounced taste and are often used for garnishing salads and snacks. Banana shallots are a long curved variety - a fashionable addition to sauces and salads. In Britain, they're at their best from mid-December to March.

Pickling onions
Available in autumn, pickling onions are baby onions and have a strong flavour. As their name suggests, they're best pickled in spiced vinegar and served with bread and wedges of cheese. They're also often roasted, in their skin, around joints of meat.

Pearl onions
2-3cm in diameter, pearl onions are larger than pickling onions, and have a sweet, nutty flavour. They're often added whole to casseroles and simmered until tender. Available in white, reddish and golden-skinned varieties.

Cocktail onions
About 1cm, or smaller in diameter, these white, sweetish onions are sold pickled in jars. They make a good accompaniment with cheese and cold cuts.

Leeks
A small root, with a thick, sheath-like stem made up of flat encircling leaves. They should have a strong fresh colour and firm dark leaves. Popular in hearty soups and sauces, leeks are also good when steamed and served with French dressing.

Garlic
Deliciously pungent, garlic is indispensable in the kitchen, and noted for its health-giving properties. Although a key ingredient in Mediterranean and Asian styles of cooking, Its only been in the past two decades that it's assumed such importance in the British kitchen - considered to be too strong for delicate tastebuds.

Garlic or onion chives are grass-like in appearance and grow to about 30cm long. When snipped, their delicate flavour makes them ideal for using in omelettes and new potato salads.

Spring onions
Also known as salad onions, they're picked when the onions are very young, and have green shoots. Often enjoyed raw, the shoots and bulb are both eaten. The more immature the spring onion, the milder the flavour.

In the kitchen...
Peeling small onions is fiddly work, try blanching them for a few seconds in boiling water before draining and running through with cold water. This loosens the skin and makes peeling much easier.

Versatile onions are used in a myriad of ways, and are ideally suited to pickling, frying, roasting, stuffing and baking.

Try roasting whole onions and garlic bulbs, in their skin, alongside joints of meat for a sweet, nutty flavour. Roasted onions can be split open and served, while roasted garlic is particularly tasteful when pushed through a sieve and added to sauces and gravies.

Use onions immediately after cutting - they lose their flavour rapidly, when cut surfaces are exposed to air.

For crisp-fried onions, lightly salt sliced onions and leave on one side for 15 minutes before rinsing and patting dry with absorbent kitchen paper. Deep-fry in hot vegetable oil until crisp, before draining. Onions cooked this way make a great garnish, especially for rice dishes. They also freeze well in secured bags.