Clean sardines,remove heads,wash and cut into 5-cm pieces.
Heat 1 tbsp oil in a pan,add onion,garlic,ginger,curry leaves and turmeric,and fry till onions turns translucent.
Mix in spice paste,fry for 2 minutes longer and remove from heat.Divide onion mixture,sardines and cambodge into 3-4 portions.
Place a large shallow pan over heat and pour in 1 tbsp oil.Place a layer of sardines followed by a layer of onion mixture.Sprinkle a portion of cambodge over this.Repeat layering and pour in enough water to just cover fish and onion mixture.
Bring to boil,sprinkle in salt,lower heat and simmer till gravy turns dry.