HOT AND SOUR SOUP

2 can (14.5-ounces each) reduced-sodium chicken broth
2 tablespoons soy sauce
1/4 to1/2 teaspoon red pepper flakes
8 ounces fresh shiitake mushrooms, stemmed, caps thinly sliced (about 4 cups)
3 to 4 tablespoons rice vinegar
2 tablespoons cornstarch
1 large egg, lightly beaten
1/2 of a 7-ounce package soft or firm tofu, cut into /4 -inch cubes, drained well*
2 tablespoons finely grated peeled gingerroot
3 scallions, thinly sliced

In a large (5-quart) pot, combine the broth, soy sauce, red pepper flakes, and 2 cups of water. Bring toa boil over medium heat. Add the mushrooms; reduce the heat, and simmer until tender, about 10 minutes.

In a small bowl, whisk 3 tablespoons of the vinegar and the cornstarch. Add to the pot; simmer, stirring, until the soup is thickened, about 1 minute.

Add the egg through a slotted spoon, and stir to form ribbons. Stir in the tofu. Remove from the heat; let stand, covered, for 1 minute.

Put the ginger in a small sieve, and squeeze to release its juice into the soup (discard the solids). Taste; add the remaining tablespoon vinegar, if desired. Serve sprinkled with the scallions.

*Note on tofu preparation: Be sure to drain the tofu thoroughly before adding it to the soup so it will soak up the flavor of the broth.

Makes 4 servings
Source: Everyday Food: Great Food Fast by Martha Stewart Living Magazine