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You’re Doing It Wrong: Potato-Leek Soup

Potato-Leek Soup

Photo by L.V. Anderson

This Saturday is Saint Patrick’s Day. If you plan to celebrate it in traditional American fashion—by drinking a lot—you’ll want to eat something before and after the revelry. It should be starchy and fatty (to absorb all that alcohol), and it shouldn’t be too pungent or heavily spiced (to avoid inflaming a soured stomach).

I give you potato-leek soup. Though the most famous version of this soup, vichyssoise, is French, a similar dish is traditionally made in Ireland—understandably, since both potatoes and leeks grow well there (even if the leek is better known as a symbol of Wales).

The one problem with potato-leek soup is that it asks quite a lot of some very mild-mannered ingredients. People eat potatoes for their texture, not their flavor, and leeks are the quiet middle child of the allium family. The two stars of potato-leek soup are the Mitch & Mickey of vegetables.

Happily, there are ways to overcome this obstacle that don’t involve adding tons of additional ingredients. The first: Make a quick stock using the green parts of the leeks (too tough to eat but full of flavor) and other vegetable trimmings. (If you’re a meat eater, throw some chicken parts in with the trimmings.) Second: Caramelize the white parts of the leeks while the stock is bubbling; this takes 20 minutes, but results in a far deeper flavor than you can get from merely sweating leeks in butter.

Speaking of which: Butter and cream are a third, not-so-novel technique for maximizing the flavor of potato-leek soup, and now is not the time to go deviating from tradition. Embrace the dairy fat—not to mention the salt shaker—and your tongue and stomach will thank you.

Potato-leek soup is excellent cold, which is a boon for two reasons. One, many regions have been having an unseasonably warm spring so far, and hot soup can be a little overwhelming when it’s 70 degrees outside. And two, you might be too hung over to reheat leftovers on the 18th.

Potato-Leek Soup
Yield: 4 servings
Time: About 1 hour, partially unattended

1½ pounds leeks, white and green parts separated
1½ pounds potatoes, peeled and chopped, trimmings reserved
1 medium carrot, peeled and chopped, trimmings reserved
1 celery stalk, chopped, trimmings reserved
Salt and black pepper
3 tablespoons butter
½ cup heavy cream
Chopped fresh chives or parsley for garnish (optional)

1. Put the leek greens and other vegetable trimmings in a medium pot, season with salt and pepper, and add enough water to cover the trimmings. Cover, bring to a boil over high heat, then adjust the heat so the mixture simmers gently.

2. While the stock is cooking, put the butter in a large pot over medium heat and slice the leek whites. When the butter melts, add the leek whites and season with salt and pepper. Cook, stirring occasionally, until they’re very tender and beginning to caramelize, about 20 minutes. Add the potatoes, carrot, and celery and continue to cook until they begin to soften, about 5 minutes.

3. Strain the stock and add enough of it to the large pot to cover the vegetables. Cover, bring to a boil over high heat, and adjust the heat so the mixture simmers gently. Cook until the potatoes are very soft, 15 to 20 minutes. Turn off the heat, add the cream, and purée with an immersion blender. Taste and adjust the seasoning, garnish with chives or parsley if you like, and serve. (Store leftover soup in an airtight container in the refrigerator for up to a week.)

Previously in You’re Doing It Wrong:
Apple Chutney
The Leap Year Cocktail