Marinate pork loin with soy sauce, white pepper, salt, water, and cornstarch
Prepare watercress by cleaning and trimming
Slice ginger into 4-5 slices
In a pot, combine chicken broth and water
Add marinated pork loin, dried scallops, and ginger slices to the broth
Bring to a boil and simmer until pork is cooked through
Add watercress to the pot
Simmer until watercress is tender
Serve hot
