Put the stock in a saucepan and bring to the boil. Heat the oil in a large-based saucepan over a medium heat. Add the onion and ginger and cook for 2 minutes, or until the onion has softened.
Add the stock and carrots and bring to the boil. Then reduce the heat and simmer for 10 – 15 minutes or until the carot is cooked and tender.
Pour into a blender or food processor and process in batches until smooth. Return to the pan and add a litle more stock or water if necessary.
Stir in the coriander and season to taste. Heat gently before serving.