Nothing could be more satisfying or warming than a bowl of hot and sour soup. Traditionally, the soup is made with pork, but I prefer to use chicken. Buy preshredded vegetables to save time, and add any leftover vegetables you may have on hand. This soup is one of those dishes that increases in flavor when reheated.
Heat the oil in a large, heavy pot over medium-high heat until hot, about 25 seconds. Add the leeks and ginger and stir-fry until fragrant, about 15 seconds. Add the tougher sections of the cabbage and the mushrooms and toss lightly for 1 to 2 minutes, until slightly softened.
Add the rice wine, partially cover, and reduce the heat slightly. Cook for about 5 minutes, until tender and dry. Add the leafier sections of the cabbage, the tofu slices, and the broth and bring to a boil. Lower the heat slightly and simmer for 15 minutes.
Slowly add the cornstarch and water mixture, stirring constantly to prevent lumps. Cook over medium-high heat until the broth has thickened, 3 to 4 minutes. The soup should have the consistency of heavy cream. Stir in the black vinegar, soy sauce, sesame oil, salt, and black pepper; taste for seasoning, adding more soy sauce if necessary. Turn off the heat and slowly add the egg, pouring it in a thin stream around the circumference of the pot. Stir the soup several times.
Ladle the hot soup into bowls, and serve immediately.
Substitute 6 to 8 dried black mushrooms or 1 1/4 ounces dried porcini mushrooms for the fresh shiitakes. Rinse and soften in hot water to cover, reserving the broth. (You can extend the broth with additional water and use in place of vegetable broth or add to chicken broth for extra flavor.) Trim the mushroom stems or tough ends, discard, and use the caps as above.
Photograph by Romulo Yanes.