Season the chicken legs with salt and pepper.
Spray a pan with low-calorie cooking spray and set on a medium heat. Add the chicken legs and fry, turning over every so often until browned on all sides. Remove from the pan and set aside.
Deglaze the pan with a little water.
Respray the pan with low-calorie cooking spray and add the ginger. Fry until it becomes fragrant.
Return the chicken legs to the pan and add the remaining ingredients (except the cornflour), and bring to the boil. Lower the heat and simmer gently for an hour.
To thicken the soup: if using xanthan gum, whisk into the pan. If using cornflour, add the cornflour and water mixture to the pan and continue to simmer until the soup is the desired thickness.
Remove the bones and serve!