Everything that goes into this soup contributes flavor. You can vary the vegetables according to your taste and what is available in your supermarket.

Makes 4 servings
Hands-on time: about 15 minutes
Total preparation time: 33 minutes

2 medium carrots
2 medium parsnips
2 small turnips
2 garlic cloves
1 medium leek
6 cups chicken broth
1 sprig rinsed fresh thyme or 1 teaspoon dried
1 bay leaf (preferably Turkish)
1 pound beef flank steak
Kosher salt and freshly ground black pepper
2 teaspoons extra virgin olive oil
1 teaspoon prepared wasabi
1/3 cup sour cream or crème fraiche
Dill sprigs for garnish

Peel and slice the carrots crosswise ½-inch thick (about 1 cup); peel and slice the parsnips crosswise ½-inch thick (about 1 cup). Peel, quarter and slice the turnips ½-inch thick (about 1 cup). Slice the garlic (about 2 teaspoons).

Trim off and discard the green part of the leek, leaving about 5 inches. Cut the white part in half lengthwise and then cut into ½-inch pieces crosswise (about 1 cup). Soak in several changes of water, lifting the leeks out of the water to let any sand sink to the bottom of the bowl; drain well.

In a large saucepan, combine the broth, carrots, parsnips, turnips, leek, garlic, thyme, and bay leaf; bring to a boil and simmer for 15 to 18 minutes.

Pat the steak dry and season with salt and pepper. Heat the oil in a large skillet over high heat until hot. Reduce the heat to medium-high; add the beef and cook for 4 to 5 minutes a side for medium rare. Transfer the steak to a plate, cover loosely with aluminum foil and let rest 5 minutes.

Stir together the wasabi and sour cream; add salt and pepper to taste. Thinly slice the steak at an angle against the grain. Add any meat juices from the steak plate to the broth.  Divide the vegetables and broth among 4 soup bowls; arrange one-fourth of the beef in the center of each bowl and top each portion with a spoonful of the wasabi cream and a dill sprig.