Measure out ½ cup of the stock and mix with the cornstarch until dissolved.
Place the remaining chicken stock, mushrooms, green onions (reserving a few for garnish), ginger, soy sauce, and white pepper in a pot and bring to a boil.
Stir in the cornstarch slurry and reduce the heat to a simmer.
Slowly pour in the beaten eggs while stirring the soup slowly. The egg will spread out into ribbons.
Turn off the heat and garnish with a few more chopped green onions. Serve immediately.
