Puree the tomato without adding water and set aside.
Heat a heavy bottomed pan with seame oil.
Once the oil is hot add mustard seeds and cumin seeds let them splutter and then add in the Channa Dal fry till golden and then add in the hing and curry leaves.
Let it splutter and wait till the shhh sound goes off.
Next add in the tomato puree.
Let it cook for 10 mins in a medium flame and then add in the Chilli powder, Salt and turmeric powder. Mix well.
Cook for another 10 mins and then add in the jaggery.
Continue cooking till it gets thick and leaves oil.