Wash the Karunai Kizhangu well in water until all the muds are completely removed. Then add it in a pressure cooker and add water till it immersed level. Close the lid of the pressure cooker and pressure cook it for 5 whistles. Once pressure released, open the cooker and cool it down. Peel the skin off from the cooked karunai kizhangu. Set this aside.

Grind coconut, cumin seeds, small onions to a fine paste by adding little water. Keep aside.

Mash the peeled yam well with your hands or using a spoon. Keep it ready. Soak lemon sized tamarind in warm water and extract the juice. Add 2 cups of water to the extracted tamarind juice along with red chilli powder, hing, turmeric powder and salt.

Add the mashed yam and coconut paste (prepared in step 2) to the tamirnad water. Mix it well to form a gravy and keep it ready.

Heat oil in a pan and add the items to temper. Fry them until mustard seeds cracks and urad dal turn brown. Then add curry leaves and red chilies. Fry for a minute. Then add onions and saute them well for 5 minutes or until they turn brown. Once the onions become sightly brown, add tamarind yam coconut paste mix to the pan. Mix well.

Add water if needed. Boil the masiyal in medium flame for some good 20 minutes or until done. Add more seasame oil while the gravy is boiling. Switch off the flame once the masiyal  becomes thick in consistency and oil separated in the edges of the pan.