Add a little bit of Oil to a hot pan and add the sliced Onions and allow it to sweat and change colour, add the Coconut and allow it to brown.
Push it to one side, add a little more oil and add Coriander, Cumin & Sesame Seeds
Leave this aside to cool
Add the Garlic & Ginger to the hot pan and once it has a little color, remove and cool as well
Remove some of the walking legs of the crab and add it to the pan and roast on both sides and allow to cool
Process the Onion, Coconut, Coriander, Cumin, Sesame Seeds, Ginger, Garlic with the Tomatoes, the spices and half of the Coriander with 1 - 2 cups of Water till smooth.
Also grind the walking legs with the other half of the Coriander and about a half cup of water
Soak the Tamarind in a cup of hot Water
Heat a half cup of Oil and add in the ground paste
Strain in the Tamarind paste
Strain in the walking leg paste
Add salt to taste
Add in the Crabs and cook for 15 - 20 mins covered, stirring in between