n a large saucepan, heat the coconut oil and the curry paste for 1-2 minutes, stirring constantly with a wooden spoon.
Add the potatoes and chicken stock to the pan and bring to boil. Now turn the heat down and simmer for 10-15 minutes until the potatoes are tender. Take the pan off the heat and blend the soup in a food processor or with a hand blender until smooth.
Now, return the soup to the pan.
Add the sweet potatoes and coconut milk and bring to the boil. Add the chicken to the soup and cook for 15 minutes until the sweet potatoes are tender, stir occasionally.
When ready to serve, add in the fish sauce and lime juice. Serve with chili flakes and fresh chopped coriander.