Heat oil in a large pot and saute the garlic and onion till translucent. Add ginger slices and continue stir fry for few seconds.
Then add the chicken breasts and bones, add light soy sauce, dark soy sauce, Chinese five spices and ½ tsp black pepper. Stir well and cook for 1 min.
Pour the warm water in, simmer with medium heat for 15 mins.
Remove the chicken breast and bones from the pot and let it cool down for few mins. - Once chicken is cool enough, shred the chicken into thin strips.
Strain the ginger slices and onion slices out from the pot and continue simmer with medium low heat.
To thicken the soup, pour tapioca and water mixture slowly into the pot from one hand and keep on stir with another hand till the sauce become thicker and glossier.
Add half of the shredded chicken strips. ( Save half of chicken strips for garnish. )
Add salt and sugar. Then pour the beaten egg slowly with one hand and continue stir with another hand. Add another teaspoon of black pepper.
The soup is ready. Taste and and add some salt or sugar if needed. Close the lid and keep it warm.