Leeks look like huge scallions (green onions). Being part of the allium family with garlic and onions, leeks taste like... onion. Typically just the white part is called for in recipes, but the entire stalk is edible.
Storage: Remove any bruised leaves. Store in a plastic bag in the fridge for up to a week.
Preparation: Since leeks grow in layers, there is often some dirt trapped between each layer. Cut the leek in half lengthwise and run under cold water to remove the dirt. For most dishes, you will saute the leeks before adding the other ingredients.
Potato Leek Soup
Garlicky Leeks in Olive Oil
Leek and Mushroom Bread Pudding
Pan Roasted Chicken with Leeks
Leek Stalk Vinaigrette