Take horsegram in a bowl and rinse it well with enough water. Add 1.5 cup of water to it.
Prssure cook legumes for 4 whistles and cook in simmer for 5 minutes. The horsegram should be cooked mushy.
When the pressure subsides, strain all the water from cooked horsegram.Take this horsegram water in a cooking vessel.
Add tamarind water, jaggery and turmeric powder to it. Boil for 5 minutes.
Meanwhile roast coriander seeds, cumin seeds, fenugreek seeds, red chillies and curry leaves till they turn slightly brown. Let it cool down and transfer to mixer.
Add coconut and 1/4 cup cooked horsegram to it. Along with required water, grind to fine paste.
Add it to the boiling horsegram water and adjust consistency. Add salt and bring it to nice boil. Next heat a seasoning pan and add all the ingredients under "to temper list". When the garlic becomes brown, temper the rasam.
