Add the tomatoes, jaggery, and tamarind paste.
Let it stand for an hour.
This makes the tomatoes darken in color due to the tamarind and becomes soft as well.
Now, place it on low heat and let it simmer for at least 10 to 12 minutes.
Add the seasonings like salt, sambar powder, chilli powder, turmeric powder, Kashmiri red chilli, and coriander seeds powder.
Cool a bit and pulse it in a mixer jar if a smooth texture is preferred or let it remain chunky.
Heat a tablespoon of oil in a tempering pan.
Add mustard seeds.
Let them crackle.
Add the curry leaves and hing.
Pour it into the tomato mixture.
Let it cool to room temperature.
Store in the fridge for a longer shelf life.
Use a clean, dry spoon to remove as needed.
Serve with curd rice, idli, dosa, parathas etc.
Use sesame oil for authentic taste.