Heat oil in a kadhai, add mustard seeds and saunf in it. Let it crackle.

Than add chopped onion and green chillies. Let it cook for 3-4 minutes.

Than add tomatoes and mix. Cover it and cook for 2-3 minutes.

Add salt, Red chilli powder and turmeric powder and mix.

Cover and cook for 10 minutes.until tomatoes cook completely.

Add sugar and mix. add green coriander leaves and mix.

Serve with chapati or parathe.