Heat 1 tbsp oil for coconut paste in a frying pan, add coconut and fry till brown, stirring constantly. Cool, mix with shallots and grind to a fine paste with ¾ cup water.
Place crabmeat in a pan with ¾ cup water and cook for 10 minutes. Set aside.
Heat 1 tbsp oil in a pan and sprinkle in mustard seeds. When they start sputtering, add shallots and curry leaves, and fry till shallots turn brown.
Reduce heat, sprinkle in spice powders and fry for a minute, stirring constantly.
Add crabmeat with its stock, salt and ¾ cup water, and cook over low heat till it comes to boil.
Mix in coconut paste, boil for 5 minutes and remove from heat. Serve with rice or porotta.