Rub your hands with mustard oil and then remove the skin of the yam. Cut the yam into one inch cubes.
Boil water with a bit of salt and add the yam pcs to it.
While the yam is boiling, peel the potatoes and cut into one inch cubes.
Chop the coconut into small pcs and set aside.
Once the yam has cooked but firm, discard the water and set it aside.
Heat mustard oil and lightly fry the coconut. Take it out and set it aside.
In the same oil, gently fry the yam pcs, give them a bit of colour and take them out.
Add more oil to the pan if needed. Then add the potatoes and stir fry them on high heat.
Now cover and let the potatoes cook till they are golden in colour and almost cooked.
Take the potatoes out of the pan.
Add dried red chilies and all the whole spices. Sprinkle turmeric powder, salt, tamarind paste and ginger paste. Add a bit of water and give this all a good mix.
Add the potatoes and the yam and mix everything together.
Add 2 cups of water and let it come to a boil.
When the gravy has somewhat thickened, add salt and sugar to taste, ghee, garam masala and split green chilies.
Serve it with rice.