Marinate prawns with turmeric, salt, and lemon juice for 30 minutes.
Dry roast all whole spices, chillies, garlic, and tamarind in 1/8 tsp ghee. Add 1 cup water, boil, cool, and grind to a fine paste.
In 2 tbsp ghee, lightly sauté the marinated prawns till they shrink. Remove and keep aside.
In the same pan, cook the masala paste with 1/2 tsp salt and 1 sprig curry leaves.
When oil starts separating, add 1/2 tsp jaggery and mix.
Add prawns back, more curry leaves, 1 tsp ghee, and cook covered for 2-3 mins.
Serve hot with plain rice or ghee rice.