A recipe for prawns from Goa.
Peel the prawns, leaving the last tail segment in place. Mix the prawns with the vinegar and 1/2 tsp of the salt and leave for 5 minutes or so.
Meanwhile put the turmeric, peppercorns, coriander seeds, cumin seeds and white poppy seeds into a spice grinder and ground to a fine powder.
Heat the oil in a medium sized pan. Add the onion, garlic and ginger and fry gently for 5 minutes. Stir in the ground spices and fry for 2 minutes. Add the ground almonds if you aren't using poppy seeds, followed by the coconut milk, tamarind water, water , three quarters of the sliced chillies and 1/2 tsp salt.
Bring to a simmer and cook for 5 minutes. Add the prawns and simmer for 3-4 minutes only so they don't overcook. Stir in the rest of the sliced chillies and the coriander.
Serve immediately with some steamed basmati rice.