In my experience, leeks are usually terribly overcooked or strangely undercooked. Either way, it’s a sad situation: It’s so easy to get them right, and results can be sublime.
Take leeks vinaigrette, the humble yet iconic French dish. In fact, the French have also named it asperges du pauvre, poor man’s asparagus. And just like asparagus, a leek needs careful cooking.
Yet even in France, where they ought to know better, it can be hard to get a good version in a restaurant. I still cringe at the memory of a seriously overcooked, offensively bland leek salad served in a famous bistro there, which more or less persuaded me to eat only leeks cooked at home.
For starters, choose the right leek. A giant leek, 2 feet long, belongs in the stockpot; even for soup, a smaller leek is better.
For leeks vinaigrette, you want a fresh-looking leek, medium size or smaller. (But don’t go too small; so-called baby leeks can often taste grassy.)
Here’s how to approach the task of leek butchery. First trim the scraggly root end, leaving a tiny bit of the bottom still intact. There is always a tough outer layer that needs to be peeled away. The top of the leek has a bright green, tender center revealed by removing the thick, gray-green leaves that surround it. With medium-size leeks, it’s best to divide the white part from the green by cutting straight across. This facilitates cooking, as the denser white part takes longer.
When you are chopping leeks for soup, cut them thinly crosswise, then wash them. For large pieces, trim to size before washing. Because leeks are grown in sandy soil, thorough rinsing is necessary to remove grit. A good soak in a large bowl of lukewarm water does the trick. Any dirt, sand or grit sinks to the bottom.
Now, pay attention: Simmer your leeks gently in well-salted water. Don’t let them boil and don’t let them go too long. They should be tender and silky, not mushy or stringy. Conversely, if not cooked enough, they’ll be unpleasantly chewy. And never refrigerate leeks once cooked; they taste far better at room temperature, or they can be browned beneath a broiler or on a grill to serve warm.
Be sure to dress them with an assertive vinaigrette. The leeks’ sweetness needs a hit of red wine vinegar and mustard, even chopped capers or anchovy. Hard-cooked egg and crisp breadcrumbs can provide welcome textural contrast.
You’ll see that a leek, treated properly, can make an excellent meal.
Bright Green Leek Soup
6 medium leeks, about 3 pounds
4 tablespoons butter
Salt and pepper
4 garlic cloves, minced
Pinch of cayenne
½ cup rice
8 cups hot chicken broth or water
10 ounces baby spinach, washed
Grated nutmeg, to taste
½ cup crème fraîche
2 tablespoons thinly sliced chives, for garnish
2 tablespoons thinly sliced tarragon, for garnish
Trim leeks of outer layer and stems. Chop white and tender green parts into ø-inch chunks (discard tough gray-green parts). Soak leeks in a large bowl of lukewarm water, swishing to dislodge sand. Drain and soak again, then lift leeks, leaving sediment behind.
Melt butter in a heavy-bottomed soup pot over medium heat. Add leeks and season well with salt and pepper. Cook, stirring, until leeks are wilted, about 8 to 10 minutes.
Add garlic, cayenne and rice and cook for 1 minute. Add hot broth and bring to a boil, then reduce to a gentle simmer. Simmer until rice is very soft, about 25 minutes. Remove from heat and let cool completely before proceeding.
Using a blender, purée raw spinach with cooled soup mixture. Strain through a fine-meshed sieve, discarding any fibrous solids. Adjust seasoning and add grated nutmeg. Thin with broth or water if necessary.
Heat soup before serving, to preserve bright green color. Garnish with a tablespoon of crème fraîche and a sprinkling of chives and tarragon. Serves 6 to 8.