For preparing Unakka Chemmeen Curry, first roast prawns in a pan. No need to use oil for roasting.
Remove it from pan and add grated coconut in the same pan and roast till all moisture evaporates.
At this stage add 1 tablespoon coconut oil and continue roasting.
When coconut's color turns golden add red chillies and coriander.
Roast till nice aroma of the ingredients are ejected from the mixture.
Let this mixture cool and after that grind this mixture in a mixer along with turmeric powder and 2 tablespoons of roasted dried prawns.
Take a mud pot and transfer the remaining prawns, mango and drumstick cut into pieces, ground masala, shallots sliced lengthwise & enough salt.
Add enough water and cook, closing the pot with a lid till the ingredients are cooked - that is almost 10 minutes.
Remove from fire. Place a frying pan on fire and pour in 2 tablespoons of coconut oil.
Add chopped shallots in it and fry till color turns golden brown. Add curry leaves into it and season prawn curry with this.
Serve hot with rice.