what part of a leek do you use

The white and light green part of a leek is the portion that is typically used in recipes. The dark green leaves are generally too tough to eat, but they can be used to add flavor to homemade stock. To prepare a leek, first cut off the stringy roots and the dark green leaves. Then, slice the leek in half lengthwise and cut it into thin half-moon slices. To clean the leek, it is recommended to soak the slices in a bowl of cold water and swish them around to loosen any dirt or sand that is stuck in the leeks.