Dry roast first red chilli, coriander seed, cumin seeds, & fennel seed and make a powder of it.

Then add jaggery in kadhai, add very little amount of water to help jaggery in melting. Then wait until it comes to a two string consistency.

Then add tamarind and keep mixing until it dries up a bit.

Finally, add salt and add spice mix add 1 tbsp vinegar (optional), and cook for another 3-4 minutes.