Peel, wash and rub yam with powdered salt. Chop it into pieces, put it in a vessel, add turmeric, ½ cup water and pressure cook till it becomes tender. Remove from fire. Reserve the cooked yam aside.
Heat oil in a pan. Add black gram, mustard, red chillies and curry leaves. when mustard splutters, add tamarind pulp and jaggery. Fry for a minute and put in cooked yam pieces and add salt. Mash the pieces gently with a ladle. Cook on a medium fire till the water evaporates.
