1/2 cup Yam (cubed, Chena)1 no Banana (cubed, nenthra kaaya)1 spring Curry leaves1/2 tsp Turmeric powder500 litre Thick yogurt1/2 portion Coconut (grated)3 nos Green chillies1/2 tsp Cumin seeds (Jeerakam)1/4 tsp Fenugreek (uluva)1/2 tsp Mustard seeds2 nos Dried red chillies2 springs Curry leaves3/4 tsp Pepper powder1 tsp Ghee2 tbsp Coconut oilSalt (As reqd) For preparing kuruku kaalan, in a pressure cooker put in banana and yam. Add turmeric powder, salt, 1 spring of curry leaves, pepper powder and required water.Allow it to whistle once.After it get slightly mashed add ghee to it and stir well.Make a fine paste of coconut, chilly and cumin seeds. Add this to the yam-banana mixture stir well.Boil it till it becomes thick and add beaten yogurt. Stir it well and turn off the stove.Heat coconut oil in a vessel and splutter mustard, fenugreek, dry chilly and curry leaves . Add it to the curry and stir well.Kuruku kaalan is ready. Serve with onasadhya.Note: 1)You can add fried fenugreek powder directly to the curry instead of spluttering it in oil.You can avoid ghee in first step and add coconut oil. Then make its quantity into 1:1.In some regions they add pumpkin(kumbalanga) with yam and banana. Kerala