Takali rasam- tomato rasam

I've been craving rasam vada for a couple of weeks, but have been putting off making it, because I thought you needed rasam powder to pull off a rasam. Then I stumbled upon this recipe that doesn't require rasam powder, and I whipped this up before I could change my mind. It tasted much better than it looked, actually.

6 tomatoes
1/2 cup coriander stems (with or without leaves)
1 tbsp ginger garlic paste
8-10 peppercorns
1 tsp jeera

Salt to taste

For tempering
1/2 tsp mustard seeds
a pinch of hing
1/2 tsp urad dal
1 sprig curry leaves
2 red chillis
1 tbsp oil or ghee

Method:
Blanche the tomatoes by soaking in boiling water for about 15 minutes. Peel the skin, chop into quarters and puree in a grinder.
Grind the coriander, peppercorns and jeera to a coarse paste, either using the grinder or a mortar and pestle. Mix the ginger garlic paste and keep aside.
Heat the oil/ ghee, and add mustard seeds. Once they start spluttering, add the rest of the tempering ingredients and fry for about a minute.
Add the ground masala and saute for a minute, then add the tomato puree, salt and about 2 cups of water.
Bring to a boil, reduce the flame, and let it cook for 10 minutes.
Serve hot.