For the rasam podi, dry roast the coriander seeds, red chillies and peppercorns for about one minute and then add the toor dal and cumin seeds. When the dal and cumin starts to brown slightly take them off the heat and let it cool a bit. In a mixer or a mortar pestle (I used the mortar pestle and I think that makes so much difference to the final product) grind the spices to a coarse powder. Add the shallots and garlic to the spice mixture and continue pounding until well blended.

In a pressure cooker, heat oil. When the oil is hot, add the cumin and onions. When the onions turn translucent, add the tomatoes, curry leaves. Fry for 2-3 minutes and then add the crab. Mix well and saute for about 2 minutes.

Pour 4 cups of water and salt and close the lid. Once the pressure builds up, reduce the flame and let it cook for about 7-8 minutes. Allow the steam to escape before you open the cooker lid.

Add the rasam podi (like I said I added only half), lime juice and some water if needed to achieve the rasam consistency. Boil for about 3-4 minutes and remove from heat.

Garnish with fresh coriander leaves and serve as a soup or with rice.