Dry roast the ingredients mentioned in the list until the dals turn golden brown. Make sure you keep the flame at low and keep mixing at all times for uniform browning. If you burn anything, I'd recommend starting over since that will ruin the flavor of the rasam completely. Cool this mixture, grind to a powder, and set aside.
Soak the tamarind in a cup of warm water, Extract juice and discard pulp.
Place the tamarind extract in a pan and add the peeled garlic, turmeric, chopped tomato, and some salt. Bring to a boil.
When the mixture has boiled for about 3 mins, add the ground spice powder. You can add half of it to begin with and taste as you go for spice and flavour. The quantity need will change depending on how strong your tamarind is and your personal preference.
Boil this mixture for about 20 mins until the raw smell leaves the tamarind mixture. Thrown in more curry leaves if you feel like it. I will be honest, I did it for the pictures.
When the rasam has boiled long enough, remove from fire and heat the ghee in a small pan. Add mustard seeds and 1/4 tsp Cumin seeds and when they splutter, dunk the entire thing into the rasam. Adjust salt.