Grind Kashmiri Chilies, cumin seeds, cloves, cardamom, cinnamon, peppercorns, mustard seeds, turmeric powder, garlic & ginger. Add red wine vinegar while grinding.
In a pan add oil and heat it. Add the onions and brown them.
Add the prawns masala and cook them for 3-4 mins.
Then add the tomatoes and saute well.
Add water, green chilies, tamarind pulp, prawn stock, kokam petals and the prawns. Give this a good mix.
Let this cook for 4-5 mins. Stir in between.