Leeks have a subtle and delicate flavor 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 flavors. Select those with crisp, brightly colored leaves and an unblemished bulb. Avoid any with withered or discolored leaves. Leeks can be refrigerated in a plastic bag up to five days. Before using, trim roots and green tops and split the leeks from top to bottom and wash thoroughly to remove the earth and sand trapped between the leaf layers. See also scallion.
Related to the onion family and used similarly for flavoring in food preparations. Leeks have a thick, cylinder shaped stalk without a bulb and have a mild onion flavor and fragrance. Leeks may be baked, broiled, braised, sautéed or microwaved. They are frequently served as a side vegetable. Purchase leeks that are fresh looking with clean white bottoms and crisp green tops. Leeks may be purchased year round; small to medium ones are the most tender. Store unwashed in a loose fitting plastic bag in the refrigerator.
Leeks look like very large green onions (scallion) in the produce section. The leek is related to both garlic and the onion even though its flavor and fragrance are milder and more subtle. Because they are so sweet, leeks are often cooked and served as a side vegetable. Wash carefully to remove the dirt between the layers. Look for leeks with lots of white.