Wash and scrub the mussels well, removing the beards and discarding any shells that dont close when lightly tapped.
Put the ginger and garlic into a food processor and add 110 ml water. Blend until fairly smooth.
Heat the oil in a large saucepan over a medium heat. When hot add the onions and saute until they turn translucent.
Add the paste from the blender together with the green chillies, turmeric and cumin. Stir and fry for a minute,
Add the coconut, salt and 225 ml water. Bring to a boil , add the mussels and mix well. Cover tightly, lower heat slightly and steam for about 4 minutes until they have opened up.