Put all the ingredients for the stock into a pan, bring to the boil and simmer for 1 hour, skimming occasionally to remove any scum. Poach the chicken thighs in the stock for 10 minutes and remove them. Mix the cornflour with a little water, stir it into the stock and simmer for 20 minutes. Strain the stock and return to the pan. Whisk in the cream of coconut.
Blanch the ginger and chil