1. Grind all ingredients for the chutney in a blender with a little water to make a paste.
2. Make angular cuts on both sides of the fish and smear the chutney in the cuts as well as on the rest of the surface.
3. Keep the fish refrigerated for 30 minutes.
4. Shallow fry the fish on both sides until they are golden brown.

To make the gravy:

1. Heat oil in a pan and add the onion paste.
2. Saute on medium heat for a minute.
3. Add the ginger and cashewnut paste. Saute for 2 mins.
4. Add coriander powder, red chilli powder, green chillies and red chillies.
5. Saute for 30 seconds.
6. Add yoghurt and the salt and cook for 3 to 4 mins. Add cream.
7. Now slide in the fried fish and cook on low heat for 3 to 4 mins.
8. Finish with black pepper and cardamom powder.