A leek is a vegetable belonging to the onion family (along with garlic, shallots, and chives). It has a long, cylindrical stalk with layers of flat, tightly wrapped leaves, and is prized for its mild, sweet, and onion-like flavor.
Unlike onions, leeks do not form a bulb. The edible parts are the white base and the light green portion of the stalk, while the tougher dark green leaves are typically discarded or used to make stocks. Leeks grow in sandy soil, so they must be thoroughly cleaned before use by slicing them lengthwise and rinsing the layers to remove any grit.
When cooked, leeks become very tender and add a subtle, delicate sweetness to dishes. They are a classic ingredient in soups (such as potato-leek soup), stews, gratins, and quiches, and can also be braised, roasted, or sautéed.
