Grind the ingredients for masala to a paste. It can be little coarse too.
Heat oil in a kadai. Add in curry leaves and onions and saute for 1 to 2 mins.
Add in prawns, salt and turmeric powder. Mix well.
Add in masala and mix well.
Cook covered for 5 to 8 mins.
Now open the lid and cook for a further 2 mins.
Add pepper and garam masala powder and mix well.
Serve with rice.