Cook yam in water along with turmeric powder, a little bit of salt and green chilly. Keep it aside.
Heat oil in a pan.
Fry the onions, till they turn golden brown.
Add tomatoes and a small pinch of salt.
In the mean time, grind the cloves and cinnamon bark to a fine powder and keep it aside.
Heat up another pan.
Add coconut, coriander seeds, red chillies and a pinch of turmeric powder.
Stir continuously, till the smell of masala comes.
Allow it to cool.
Grind the same into a paste with some water taken from the vessel in which yam was cooked.
Take a larger vessel and add the cooked yam(with water), coconut mixture, onion-tomato mixture and the clove-cinnamon powder.
Add coriander leaves and salt and mix well.
Allow it to boil.