In a bowl, add yogurt and salt. Whisk well. Now add the cut banana stem and keep the bowl aside.
Place a small pan above the stove and add 1/2 teaspoon. When the oil is heated. Add mustard seeds and urad dal. Once the splutter and become brown, add the green chillies and curry leaves. Stir
Now add this to the bowl with yogurt and banana stem. Mix well and serve