Chicken Egg Drop Soup

Bring the chicken broth, ginger and scallions to a boil in a saucepan. Cover and reduce heat to medium-low and simmer 20 minutes. Remove from heat and strain into a large bowl and discard the ginger and scallions. Return the broth to the saucepan and add the wine or Sherry. Meanwhile, whisk the chicken , sesame oil, 1 tablespoon cornstarch, 1/4 teaspoon salt and 1/4 teaspoon white pepper in a bowl. Refrigerate until ready to use. Dissolve the remaining 3 tablespoons cornstarch in 1/4 cup water. Return the broth to a simmer over medium heat and add the cornstarch mixture and cook, stirring, until glossy and slightly thickened, about 4 minutes. Add the chicken and simmer until cooked through, about 1 to 2 minutes. Drizzle the eggs into the soup a little at a time, creating thin sheets of cooked eggs. Gently stir in the watercress and serve.