If prawns were frozen and then defrosted, make sure they are drained well of any liquid. In a large bowl, combine them with salt and chilli powder, set aside.
In a large frying pan, preferably cast iron, heat the coconut oil over medium high heat and add the curry leaves. Stir for a few seconds, then add the onions, garlic and the fresh red chilli.
Fryfor 5 - 10 minutes, stirring regularly until the onions are golden brown and char in places.
Sprinkle the fenugreek powder (or kasuri methi) and fry for a few seconds, stirring. You should be able to smell the spice now.
Add the tomato puree, chilli powder, fresh coconut, tamarind paste, coriander powder and the sugar. Fry until the oil comes out of the mixture. This could take a few minutes. If you want to hurry the process, add another tbsp of coconut oil. It is important to fry the mixture very well at this point before the prawns go in.
When the tomato chilli mixture looks fried, add the prawns, mix well and fry until the prawns are cooked.
Taste, adjust the salt, heat and sourness to your preference. Enjoy with steamed rice.