Clean & prepare the Shrimp
Soak the red Chillies either overnight or in hot water for at least an hour
Process all the whole spices, add the chillies, turmeric, ginger, garlic, vinegar and water as needed to form a smooth paste
Strain this masala (optional)
Heat some oil and saute the onions till golden brown
Add the masala paste, the tomatoes, salt and cook till the tomatoes soften
Add water as required
Add the tamarind and chilli powder and continue cooking till the tomatoes get soft
Add water and salt as the mixture thickens
When you have a smooth gravy after about 30 mins, add the kokum
Finally add the prawn and shrimp, submerge in the gravy and allow to cook for a few minutes