Leeks have a subtle and delicate flavour that is milder and sweeter than that of onions. The white part grows underground and is formed of sheathed cylindrical leaves; it is the more tender part of this vegetable and that which is the most appreciated and most commonly used. The white adds a subtle touch to various dishes without masking other flavours. The green ends are usually cut off at the point where they separate from the bulb and are primarily used as a flavouring ingredient in broths, soups, and stews. This vegetable, which grows to between 45-90cm high, is harvested when the bulb is at least 2.5cm in diameter.

History

A biennial garden vegetable thought to have originated in central Asia, leeks have been known since antiquity and are mentioned several times in the Bible. Already cultivated by the ancient Egyptians, this vegetable was probably introduced into Great Britain by the Romans, where it came to be held in high esteem by the Celts. The leek is regarded as the "national vegetable" of Wales.

Nutritional Value

Raw leeks are an excellent source of folic acid and a good source of iron and potassium; they also supply vitamin C, vitamin B6 magnesium, calcium, and copper. Leeks are said to be laxative, antiseptic, diuretic, tonic, and antiarthritic. They are also known for their cleansing effect on the digestive system.

Buying

Look for leeks that are straight, firm, and intact, they should have bright green tops and be free of brownish patches. Avoid limp leeks, as well as those with cracked or swollen bulbs or dried-out and discoloured leaves.

Storage

Leeks can be stored in the refrigerator for about 2 weeks. It is also possible to store them, unwashed, in a cool damp place (90-95% humidity), where they will keep between 1 and 3months.

Once cooked, this vegetable will keep for only about 2 days in the refrigerator, after which it tends to spoil rapidly and become indigestible.

Leeks can be frozen, but their texture and flavour are altered when thawed. Cut raw leeks into slices, or blanch them whole for 2 minutes, before freezing. Frozen leeks will keep for about 3 months, for maximum flavour, cook them without thawing.

Preparing

It is important to wash leeks thoroughly to rid them of the earth and sand trapped between the leaves. To do so, trim off the rootlets and the green tops, leaving a little green if desired, and remove any wilted outer leaves. Make a few equally spaced lengthwise cuts in the bulb stopping about 5cm from the base, and pry open the layers of leaves; wash thoroughly under running water and drain.

Cooking

This vegetable should be cooked briefly, as it tends to become soft and mealy when overcooked. To ensure uniform cooking, buy similarly sized leeks. When cooking whole or split leeks, allow 15-20minutes if boiling them and 25-35 minutes if braising or baking them. Sliced leeks can be sauteed for 3-5 minutes, simmered for 10-15 minutes, or melted in butter for 20 to 25 minutes.

Using

Leeks are eaten raw as well as cooked. Finely chopped raw leek is often added to salads; it can also be used either in combination with or in place of onions. Sometimes dubbed "poor mans asparagus" in Europe, leeks can be cooked and prepared in much the same way as asparagus.

They are excellent with vinaigrette or a cream sauce and are often combined with potatoes, as in the famous vichyssoise, a delicious soup made with pureed potatoes and leeks and traditionally served cold. Leeks can also replace chicory in dishes baked au gratin.

The green part is often used to add flavour to stocks, stews, and other similar dishes; it can substitute for shallots or chives. Leeks are a good accompaniment to veal, ham, and cheese, and blend well with lemon, basil, sage, thyme, and mustard. The white part of leeks can be finely shredded or cut into strips and used as flavouring in stocks and court bouillons.