Cut off green tops of leeks and remove outer tough leaves. Cut off root and cut leeks in half lengthwise. Fan out the leeks and rinse well under running water, leaving them intact. Cut leeks into 2-inch lengths. Holding the leek sections cut side up, cut lengthwise so that you end up with thin strips, known as the chiffonade cut, slicing until you reach the green portion. Make sure slices are cut very thin to shorten cooking time. Let leeks sit for at least 5 minutes before cooking.