Add the chicken stock and bring to boil. If you would like to add the egg, you can drop it in at this point. Cover and simmer for 2 minutes or until the egg white is cooked but the egg yolk is still raw. If you are not using the egg, proceed to 3.

Add the soy milk and heat it until it is hot. (Do not boil on high heat once you have added the soy milk as it will curdle)

Remove from heat, garnish with finely chopped green onions and sprinkle the chili oil if desired. If you are adding noodles, boil them while you are making this soup. Drain, and place it in a bowl and pour the soup over it.