Clean and wash the prawns nicely.
Add red chilly powder, turmeric powder and salt.
Add 2 cups water and keep aside.
Cut the veggies and keep it ready.
Grind coconut with cumin seeds, shallots and little water to make a thick smooth paste.
Heat oil in a clay pot and splutter mustard seeds and fenugreek seeds. Add shallots and saute until it is golden brown in color.
Add tomato, green chilly and saute for 3 minutes.
Add prawns and masala water into it and cook for around 10-15 minutes. Add mango pieces along with it.
Add the ground paste to the curry. Add water if required to get the correct consistency.
Mix well and bring it to a slow boil.
Serve hot with rice.