How to Peel Dirty Leeks
Leeks are an infamous dirty vegetable and this is due to the way they are grown (in a lot of mud). Most farmers push the soil up and around as it grows, leaving the stem pale and tender (the dark green parts are much tougher than the white and light green parts). This, of course, causes dirt and sand to accumulate in many layers of the onion. It doesn’t really matter; you just need to peel them before you eat them.
I prefer the whole leek peeling method like the one used by David Lebowitz . Keeping the leeks intact while you wash will make them easier to handle. Instead of a bunch of small leeks floating in a bowl, you only need to watch out for one, large, fanned vegetable. Like Lebowitz, I start by trimming the really tough, dark green parts of the vegetables (to save them for broth or steaming ), as well as the ends of the root vegetables. (Don’t chop off the entire root, though – that’s what holds this whole operation together.)
After trimming both ends, cut one large cut through the whole leek — starting about half an inch from the root — all the way to the end. Rotate 90 degrees and repeat.
Once the leeks are fanned and tender, toss them in a clogged sink or very large bowl of water. Shake a little, then visually inspect the inner layers to make sure you’ve removed all the dirt. If it is still dirty, change the water and try again. (Some leeks are dirtier than others.)
When the leeks are clean, place them on a tea towel or dish drainer to dry. You can leave them whole (a good move if you want to grill them over hot coals ) or cut them into smaller pieces for soups, stews, and sauces.