Cut plantain stem into fine pieces, removing the fibres(thread like portions) if present. Wash these pieces in water(if required, add some buttermilk in water to get a more white colour).
Heat 3 tsp of oil in a fry pan, add 1 tsp mustard seeds. When it pops, add 1 tsp urud dal, 3 tsp moong dal, 1 red dried chillie and roast lightly. Add the cut pieces and a little salt. Add 1/2 cup water, cover and leave it in low heat for 10 min(until fully cooked and the water dries up).