Dry roast all the ingredients under "for sambar powder" till aromatic. Allow to cool slightly and then powder coarsely. Reserve it aside.
Soak the moong dal for 15 minutes. Drain.
Add the dal along with all ingredients and the prepared sambar powder. Pour one cup of water and give a good mix.
Pressure cook for three whistles and switch off. Allow the pressure to go. The dal would be mushy and the vegetables would be cooked.
Add more water and bring to a boil as required. Add a pinch of sugar if the sambar is too tangy.
Heat ghee in a small pan. Fry the ingredients for tempering till done. Add in to the sambar and keep on closed lid till time to serve.