1. Wash crabs, pull the top shell from the body.
2. Discard the stomach bag attached to the shell below the eyes.
3. Discard greyish white dead man's finger and wsah well.
4. Cut each crabinto 4 pieces. Wash crabs well.
5. Grind to geather grated coconut, garlic, green chilies, coriander leaves and ginger.
6. Heat oil. Add mustard seeds, chopped onions and curry leaves.
7. When lightly fried, add ground spices.
8. Add salt. Mix the grainding stone or very little water and cook over slow fire till crab is done and almost dry.