Put all the stock ingredients into a pan, bring to the boil and simmer for 1 hour, skimming occasionally to remove any scum.
Mix the cornflour with a little water and stir it into the stock. Simmer for 20 minutes then strain the stock and return it to the pan. Add the cream of coconut and whisk it in. Blanch the ginger and the chillies in water for 5 minutes to remove the harsh flavours