7 cups homemade or canned chicken broth
1/2 cup rice vinegar
2 tablespoons soy sauce
1 cup finely chopped sweet onion (such as Vidalia, Texas 1015, Walla Walla Sweet, or Oso Sweet)
1 cup chopped green onions (all the white and half the green portions of about 6 onions)
1 (1 pound) block firm tofu, drained well and sliced into 1/2-inch long by 1/4-inch thick julienne strips
10 dried shiitake mushrooms, soaked and sliced into thin shreds (see note)
3 eggs, lightly beaten

In a large pot, combine the broth, vinegar, soy sauce, sweet onion, green onions, tofu, and mushrooms. Bring the mixture to a boil over medium-high heat, reduce the temperature to medium-low, and simmer gently, uncovered, for about 15 minutes to give the flavors a chance to merge and develop. Adjust the seasonings, adding additional vinegar or soy sauce, if desired.

Just before serving, bring the soup back to a slow boil. While stirring the soup, slowly drizzle in the beaten eggs. They will cook quite quickly in the hot broth and blossom out into feathery strips and bits. Serve immediately.

Serves 8.

Variation: For a spicier soup, stir in 1 to 2 teaspoons hot chile-garlic paste and a dash of sesame oil.

Note: To reconstitute the dried mushrooms, place them in a deep bowl, cover with boiling water, and let sit for about 30 minutes, or until the mushrooms are soft and pliable. To keep the mushrooms submerged as they reconstitute, place a saucer or plate on top and weight it with a heavy object, such as a can or a coffee mug.