Heat around 1½ tsp of oil in a pan on medium heat.
Add jeera, then add red chillies. Once the the chillies are warm enough, take it out and keep it aside.
Then add cut onions and sprinkle some salt. ( The salt helps cook the onion faster)
Once the onions become translucent, add tomatoes.
Add curry leaves, tamarind or jaggery, and turmeric powder.
Mix and let the tomatoes cook well.
After around ten minutes, or once the tomatoes are cooked well, turn off the heat and let it cool.
Once it is cooled completely, grind this along with chillies and salt to a fine paste.
Transfer it to a bowl and prepare the seasoning.