Wash the rice well, swirling it gently in four changes of water. By the end there should be little cloudiness left in the water. Drain.
Put all of the ingredients in a pan with a pinch of salt and bring to the boil, stirring to stop the coconut milk scorching. Boil hard for about 10 seconds, still stirring, then turn the heat to the lowest. Cover with a lid and simmer for 15 minutes.