Hot-and-Sour Seafood Soup

Heat the vegetable oil in a large pot over medium-high heat. Add the scallion whites and cook until slightly tender, 2 to 3 minutes. Stir in the ginger and cook about 1 minute. Add 7 cups water, the soy sauce, sugar , salt to taste, 3/4 teaspoon pepper and the mushrooms. Cover and bring the broth to a simmer . Mix the cornstarch with 1/4 cup cold water and gradually stir into the broth . Bring to a gentle boil , stirring; the broth will thicken slightly. Add the scallion greens, tomatoes and white fish to the broth, and simmer until the fish is opaque, about 3 minutes. Add the scallops, vinegar, and salt and pepper to taste (the scallops will cook instantly from the heat of the soup ). Ladle into bowls. Per serving: Calories 200; Fat 5 g (Saturated 1 g); Cholesterol 46 mg; Sodium 274 mg; Carbohydrate 15 g; Fiber 2g; Protein 25 g Photograph by Antonis Achilleos