Soak the shiitake mushrooms for 20 minutes in just-boiled water, then cut into thin slices.
Wash the bamboo shoots with water then soak in just-boiled water for 15 minutes. Drain and set aside.
Prep all your other ingredients.
Add the chicken stock, water, shiitake mushrooms and ginger to a pot on medium high and bring to the boil.
Once the water is boiling, add the chicken and cook with the lid partially on for 4 - 6 minutes or until cooked. If the water is boiling too vigorously turn it down to medium - low.
Once the chicken is done, take it out and let it cool in a covered bowl (Note 1). Then shred the chicken in to small pieces.
Add the bamboo, tofu, salt, pepper, sugar, white vinegar and fish sauce. Cook with the lid partially on for another 5 minutes on medium low.
Add the beaten egg slowly to the pot while gently stirring it with a spoon.
In a small bowl, combine the cornstarch and cold water. Then add it to the pot and stir it into the soup.
Add the chicken back into the soup and let it come to the boil.
Check the seasoning, sourness and consistency of your soup (Note 2)
Garnish and serve.