Remove the skin of the yam and wash it.
Cut the yam into big chunks and steam cook till it is soft.
:- Please use gloves to avoid itching on your hands.
Cool and mash it well.
Extract thick juice from tamarind.
Heat sunflower oil in a kadai.
Simmer it and add turmeric, chilli, coriander powder, jeera powder and salt.
Add tamarind juice.
When it boils, add the mashed yam.
Keep the flame low and stir it occasionally.
Add the powdered jaggery after around 10 mins.
Wait till the oil leaves the side of the kadai.
Remove it from fire.
Heat seasame oil in a small kadai.
Splutter mustard seeds followed by black gram, dry red chillies and curry leaves.
Pour it in the yam curry.
:- Serve with chapathi or hot rice with seasame oil.
:- You may use coconut oil for seasoning instead of seasame oil.