Leeks are grown mainly in Europe and other areas around the Mediterranean sea. Its taste is similar to that of its relatives, onions and garlic, but is much milder. Leeks give many dishes a richer flavor. They work well in soups, vegetable side dishes, quiches, and casseroles. You can also eat them raw or grated in salads.
From Wikipedia: “The leek is a vegetable, a cultivar of Allium ampeloprasum, the broadleaf wild leek. The edible part of the plant is a bundle of leaf sheaths that is sometimes erroneously called a stem or stalk. Historically, many scientific names were used for leeks, but they are now all treated as cultivars of A. ampeloprasum. The name 'leek' developed from the Anglo-Saxon word leac. Two closely related vegetables, elephant garlic and kurrat, are also cultivars of A. ampeloprasum, although different in their uses as food. The onion and garlic are also related, being other species of the genus Allium.”
“Leeks have a mild, onion-like taste. In its raw state, the vegetable is crunchy and firm. The edible portions of the leek are the white base of the leaves (above the roots and stem base), the light green parts, and to a lesser extent the dark green parts of the leaves. One of the most popular uses is for adding flavor to stock. The dark green portion is usually discarded because it has a tough texture, but it can be sautéed or added to stock. A few leaves are sometimes tied with twine and other herbs to form a bouquet garni.
Leeks are typically chopped into slices 5–10 mm thick. The slices have a tendency to fall apart, due to the layered structure of the leek. The different ways of preparing the vegetable are:
Leeks are an ingredient of cock-a-leekie soup, leek and potato soup, and vichyssoise, as well as plain leek soup.
Because of their symbolism in Wales (see below), they have come to be used extensively in that country’s cuisine. Elsewhere in Britain, leeks have come back into favor only in the last 50 years or so, having been overlooked for several centuries.”
“The leek is one of the national emblems of Wales, worn along with the daffodil (in Welsh, the daffodil is known as "Peter's leek", Cenhinen Bedr) on St. David’s Day. According to one legend, King Cadwaladr of Gwynedd ordered his soldiers to identify themselves by wearing the vegetable on their helmets in an ancient battle against the Saxons that took place in a leek field. The Elizabethan poet Michael Drayton stated, in contrast, that the tradition was a tribute to Saint David, who ate only leeks when he was fasting. ...
In Romania, the leek is also widely considered a symbol of Oltenia, a historical region in the southwestern part of the country.”