Heat oil in a pan or a kadai.
Add curry leaves, chopped onions, slit green chillies and fry, till half cooked.
Add salt, ginger and garlic and fry, till brown.
Add garam masala (optional), chicken/mutton masala powder, pepper powder and food color and fry well, till the raw taste goes off.
Add prawns.
Add very little water, if needed.
Keep stirring at regular intervals, to avoid getting it burnt at the bottom of the pan.