Chinese Hot and Sour Soup
 
8 cups low-sodium chicken broth
1 ten-ounce whole boneless and skinless chicken breast
2 teaspoons toasted sesame oil
2 cloves garlic, minced
1 small onion, cut lengthwise into 1/4-inch-thick slices
4 ounces shiitake mushrooms, stem and slice 1/4 inch thick
2 carrots, peeled and cut into matchsticks
1½ teaspoons grated ginger
1 teaspoon freshly ground black pepper
Pinch cayenne pepper
½ teaspoon salt
3 tablespoons cornstarch
3 tablespoons low-sodium soy sauce
6-8 tablespoons rice-wine vinegar
1 large whole egg, plus 1 large egg white, beaten
3 large scallions, cut crosswise into 1/4-inch-thick slices
6 ounces firm or extra-firm tofu, cut into 1/2-inch cubes
 
1.       In a small saucepan, bring 3 cups chicken stock to a boil. Add chicken breast; poach until cooked through, about 12 minutes.   Let cool and pull the breast into long shreds. Set aside. Pass stock through a cheesecloth-lined sieve set over a medium bowl; set aside.
2.       In a 6-quart saucepan, heat oil over medium-low heat. Add garlic and onion, and cover. Sauté, stirring occasionally, until translucent, 6 to 7 minutes. Add mushrooms and sauté until tender, about 5 minutes. Add reserved and remaining chicken stock, carrots, ginger, black pepper, cayenne, and salt; bring liquid to a boil. Reduce the heat, and simmer until carrots are tender, about 3 minutes.
3.       Place cornstarch in a small bowl, and slowly whisk in soy sauce until cornstarch has dissolved. Whisk in vinegar. Slowly whisk cornstarch mixture into soup. Simmer until soup is clear, 5 to 7 minutes. Add reserved chicken, and continue simmering until chicken is heated through, about 2 minutes. Turn off the heat. 
4.       Slowly pour beaten eggs through a perforated spoon into soup.  Cover soup, and let stand 1 minute. Remove the cover, and gently stir. Add scallions and tofu. To serve, ladle into individual bowls. Makes 8-10 servings