In a kadai, heat 2 tbsp oil and fry onions and red chillies until onions are brown.
when it turns brown, add chopped tomatoes, rock salt and mix well.
add 1/4 cup water. close and cook further for 5-10 minutes or until the tomatoes are soft.
open and mash it well while it cooks.
cool and grind it to a fine paste.
heat 1 tsp oil in the same pan and crackle mustard seeds, urad dal and curry leaves.
when it turns crisp, add the prepared chutney, 1/4 cup water and mix well.
close the kadai partially and cook further for 5 minutes until the desired consistency is reached.
put off the flame and serve hot with breakfast of your choice.