As you can see, leeks aren't the cleanest vegetables around! Not only do their roots hold dirt like Fort Knox, but grit drifts in from above and gets wedged between the oniony layers.
Before using them in recipes like yesterday's Arugula Vichyssoise or the amazing leek mat that Jill made for the smoked fish she served at her wedding, we need to clean them thoroughly if we want to avoid eating more minerals than we intended!
First, cut a quarter inch or so off the bottom of the leek, removing the roots completely.
Next, cut off the upper, dark green part of the leaves where they start to unfurl from the leek. These are too fibrous to eat, but they can be used to flavor soups and stocks.
The light green and white portion that remains is the edible part of the leek. Cut this in half lengthwise.
Rinse each half under cool, running water. Use your fingers to flex the leek and rinse between the layers while still keeping the layers relatively intact.
Once you've washed away all the grit, you can continue chopping the leek as directed in the recipe.
Since the leek is usually going into a soup or stir-fry, don't worry about drying it before cooking. If a recipe requires dry leaks for some reason, you can run it through a salad spinner or press it between kitchen towels after chopping it into pieces.
Related: How to Dice an Onion
(Image credit: Emma Christensen for the Kitchn)