First chop onions and garlic, subsequently take a pan and add 1 tablespoon oil. When oil is hot, add chopped onion and garlic. Fry this till onion turns brown.
Take a bowl/ jar and add mint leaves, large pieces of tomatoes, green chillies and ginger.
To this jar add the sauted onion and garlic, and then blend to a smooth paste in mixer or using a blender.
Use the same pan again and add 1 tablespoon of oil, when oil gets hot, add cumin seeds and mustard seeds. Fry till seeds crackle, add bayleaves.
Now add garam masala, red chilli powder, coriander powder, black cardamom, and prawn curry powder, and fry for half a minute.
Now add the paste created on step 3, add salt and let it cook for 5 mins.
Lastly, add prawns and let it cook for 7-8 mins on medium heat. Your curry is now ready. Plate it with garnishing with coriander.