Dry roast all whole spices on low heat for 2 minutes
Grind roasted spices with coconut and little water to form smooth paste
Marinate prawns with salt turmeric and lemon juice for 15 minutes
Heat 2 tbsp oil and fry prawns for 2 minutes and keep it aside
In same pan, heat 2 tbsp oil. Saute onions and green chillies until onions are translucent
Add tomatoes and saute for 3 minutes
Add salt tamarind paste 1/2 cup water and ground paste. Mix well. saute and cook for 6 minutes
Add water and prawns. Simmer and cook for 3 minutes
Add coconut milk and give it a stir. Switch off. Do not cook after adding coconut milk
Cover and rest for 20 minutes
Garnish with coriander leaves and serve warm