Heat oil in a large frypan over medium heat.  Add curry leaves and cook until they are crispy.  Carefully remove the leaves from the oil using a slotted spoon, drain on paper towel. 

Add oil back to the heat, add garlic and spices and cook until the seeds begin to pop and garlic is lightly golden.   

Serve curried prawns over cooked rice, spoon over the tarka and scatter with crispy curry leaves to garnish.