Wash and clean the chopped banana stems. Boil them in slightly salted water till al dente/ slightly soft. Alternately pressure cook them for 2 whistles in a colander . Cool completely.
In a skillet, add ¼ tsp of oil. When slightly hot, add methi, cumin , channa dal, coriander seeds, dry chillies, red chillies, hing, turmeric one after another and roast till the dal slightly browns. Do not burn. Cool.
Dry grind the masala with coconut. Once completely dry, add a little water to make a thick paste (consistency of milk shake).
Add this mixture to the curd. Whisk well. Add salt as required. Add 2 – 3 tbsp of water if you feel it is too thick.
In a large bowl, add the cooked banana stem. Add the curd mixture to this
In another pan, add oil, make the tempering. When the mustard stops spluttering, add this to the banana stem+ curd mixture from above.
Adjust salt if required.
Serve hot with steamed rice and Sambhar / curry