Dry roast black pepper and jeera (separately) and pound them into a coarse powder using a mortar and pestle.
Heat a kadhai and add ghee, followed by some mustard seeds (use half the quantity as prescribed in ingredients).
Once mustard crackles, add hing or asafoetida (use half the quantity as prescribed in ingredients).
Now add some curry leaves and chopped tomatoes
Allow the tomatoes to cook and turn mushy (try and mash with the back of your spoon / spatula)
Add turmeric powder, water as per your desired consistency and allow it to reach a boil.
Once it boils, add the coarse black pepper and jeera powder
Mix well, add salt to taste and allow it to simmer on low heat for atleast 5 to 7 minutes.
Now add the cooked Toor dal or arhar dal and mix well
Check for salt and add more if required
Add finely chopped coriander leaves and mix well
Once the Rasam turns frothy on top, switch off the flame and prepare for tempering
Temper the Rasam with some mustard seeds, red chillies, ghee and asafoetida and pour it over the Rasam.
Mix well and add some more finely chopped coriander leaves.
Serve piping hot as Soup or mix with Steamed Rice and enjoy