Add the chicken stock, coconut water, lemongrass, ginger and shallot to a pot. Cover and bring to a boil.
Once the mixture is boiling, reduce the heat and let the soup simmer. You should be able to smell the fragrance of the herbs after 5 minutes, if not increase the heat slightly . Allow the soup to simmer for another 10-15 minutes to extract all the fragrance of the herbs.
Add the tomatoes and lime juice & allow the soup to return to the boil.
Season with fish sauce, or salt, to your taste.
The above makes the basic soup base which can be drunk as it is. You can also add prawns,chicken, fish, abalone, Chinese cabbage, mushrooms and chilli to the soup for a heartier dish.
To bulk the dish into a main, add either noodles or rice. I like to add tang hoon (mung/ greenbean vermicelli) which is first soaked in hot water. Once the noodles have softened, they are then added to the soup. Give everything a stir for 1-2minutes then serve.
Alternatively, you could add cooked rice to the soup once the soup has finished simmering to make “paofan” or submerged rice.