Roast the cumin seeds, mustard seeds, fenugreek seeds, dhania seeds, black peppercorns and dried chillies in a pan on low heat for about 3 minutes, tossing frequently as to make sure not to burn the spices
Once cooled, grind the spices into a powder and keep aside
Heat a large pot on medium to high heat and add the oil, onions and 1 sprig of curry leaves
Allow the onions to get translucent before adding the crushed garlic - mix well
Now add 2 heaped tablespoons of the freshly ground spice mix that was just ground and also add corse salt, according to taste
In goes the cleaned crab, mix well, place the lid onto the pot and simmer for 5 minutes
Add the chilli powder, masala and turmeric powder and another tablespoon of the freshly ground spice - give it a good toss
Add the crushed tomatoes and the tomato paste, mixed with a dash of water , mix well
Add hot water and the tamarind and the rest of the curry leaves and simmer for about 10 -15 minutes until thickened, add sugar to balance the acidity
Garnish with kasuri methi and freshly chopped coriander leaves