Put chicken stock in a small saucepan and bring to a light simmer over medium heat.
Whisk eggs in a small bowl until whites are well mixed with the yolk. Add a few drops of fish sauce to add flavor to the egg mixture, otherwise, season with salt.
Dissolve cornstarch in cold water and mix until it reaches a milky consistency. Pour into simmering chicken broth and let simmer to reach desired thickness. (Add more cornstarch mixture if desired, until broth reaches desired consistency.
Remove broth from heat. Pour thin stream of beaten egg mixture and whisk it rapidly into the hot chicken broth with a fork.
Serve in small bowl and garnish with chopped scallions, cilantro, grated ginger, and white pepper