Heat oil in a pan or a kadai.

Fry the onions until just brown.

Add ginger-garlic paste and green chillies. Fry for a minute.

Add the chopped tomatoes and all the masala powders except garam masala and salt.

Add salt, mix well and cook till the oil separates from the mixture.

Add the prawns and cook till its cooked.

:- Take care to see that prawns are not over cooked. It will get cooked in less than 7 mins.

Add garam masala powder and mix well.

Remove from heat.

:- Serve hot.

:- You can adjust the dryness of the gravy before adding the prawns. Cook the tomatoes till dry if you dont want the gravy. For a milder curry, add coconut milk when prawns are cooked and repeat the remaining steps.