Marinate the cleaned prawns with turmeric powder, red chilli powder and salt. Keep aside for at least 15 minutes.
Heat oil in a large pan; add the onions and garlic, sauté till the onions have turned light brown.
Add the coriander powder and cumin powder; mix well to combine.
Next add the tomato puree and the jaggery; mix well and allow to cook on low heat without adding any water. Once the excess moisture has evaporated, add the chopped tomatoes and allow to cook further on low heat till you get a thick consistency.
Next add the marinated prawns along with the vinegar and half of the coriander leaves.
Cook covered on medium heat till the prawns are done, stirring in between.
Remove and garnish with the remaining coriander leaves.
Serve warm with rice and dal.