Method:

1. Clean and devein the prawns. Put the prawns in a large bowl and sprinkle salt on them. Set them aside.

2. Using a dry pan over medium heat, toast the dried red chilies, cumin seeds, mustard seeds, cloves, and cinnamon until they begin to release their aroma. Take off from the heat and cool.

3. Grind the ginger, garlic, and toasted spices into a smooth paste using the vinegar. You can do this with a small food processor or a mortar and pestle.

4. Heat the oil on a medium flame in a wok-style pan. Add the prawns and stir fry until opaque. Remove from the pan and set them aside.

5. In the same pan, fry the onions until they are light brown. Add the tomato and fry until soft.

6. Now add the spice-vinegar paste, sugar, and salt to taste. Fry until the oil begins to separate from the spice mixture.

7. Add the prawns to this spice mixture, mix well and cook for 2 to 3 minutes.