Leeks are part of the allium family of root vegetables related to onions, garlic, and shallots. Leeks have a mild onion flavor. While leeks have a white base and green top similar to green onions, only the lower white part of the plant is eatable. To prepare leeks, start by cutting off the bottom roots. Slice the outer layer and peel away from the leek. You may see dirt coated onto the leek. Wash this off. As you peel additional layers you may see a similar layer of soil. This will be washed off after you slice the leek. Thinly slice the white end of the leek. You can use it until the green top, which is tough and fibrous. Place sliced leek in a colander and rinse under running water. Dry on paper towels. Saute, and add to soups, and other cooked and roasted recipes.