Heat 1/4 tbs oil in a kadai. Once they get heated up add the vadagam and cook for couple of minutes till the raw smell disappears. Then throw in the garlic and let it brown a bit. Add the red chillies and give it a complete stir. Finally mix in the tomatoes, tamarind and onions and cook covered for 15- 20 minutes. Remove from flame and let it cool.
Once cooled, grind them to a fine paste (Don’t use water).
Heat the remaining oil in a small kadai. Once they get heated up, add the mustard seeds and let it splutter. Throw in the urad dhal and curry leaves and cook for couple of minutes. Mix them into the chutney and add salt to taste.