Wash and clean the crabs with water. Cut in to pieces.
Heat coconut oil in a pan and add mustard seeds let it splutter and add finely sliced onions. Cook till the onions turn brown.
Add ginger garlic paste and chopped green chillies. Cook for a few minutes.
Add Kashmiri chilli powder, coriander powder and turmeric powder. Cook for a few minutes.
Add sliced tomatoes, salt & curry leaves. Cook for 3 minutes.
Add cleaned crabs and mix well. Add hot water.
Cover and cook in a low flame for 10 minutes.
Cook till the crabs is done and the gravy is almost dried.
After 10 minutes add garam masala and pepper powder and mix well. The tasty Kerala crab masala is ready.