Remove the skin of raw banana, yam and chop them into bite sized pieces.
Cook it with enough water along with 1/4 teaspoon turmeric powder and little salt (You can even pressure cook for 2 whistles). The veggies should be cooked soft.
Soak channa overnight and pressure cook for 5 whistles or until soft.
Grind the ingredients listed under 'to grind' to a semi fine paste. Set aside.
Now in a pan add cooked veggies along with black chana, add the coconut paste, check for salt and adjust accordingly and sprinkle little water. Do not add more water.
Saute till raw smell of coconut leaves.
While it gets sauted prepare the tadka - heat coconut oil in a tadka pan add the ingredients listed under 'to temper' let it splutter.
Dry roast coconut till dark reddish golden brown.
Once the coconut raw smell leaves from the curry and the curry becomes like a thick curry add roasted coconut and tadka tempering to the curry, mix well and switch off.
Garnish with roasted coconut. Serve hot with rice, sambar and papadam.