Heat sufficient water in a steamer. Trim the stems of the arbi leaves an roll a rolling pin on the back side to soften the leaves.Place besan in a bowl, add ginger paste, green chilli paste, red chilli powder, coriander powder, cumin powder, turmeric powder, crushed sesame seeds, tamarind pulp, jaggery and sufficient water and mix into a thick paste. Add salt and mix again.Apply this paste all over the back side of an arbi leaf. Place another leaf over this with its pointed end opposite the first one. Apply the paste over this too. Fold the sides slightly and tightly roll.Keep the rolls on a perforated plate and keep it in the steamer. Cover with the lid and steam till done. Take the rolls out and let them cool completely. Slice into roundels.Heat oil in a non stick pan. Chop coriander leaves. Add asafoetida, mustard seeds and sesame seeds to the oil and when they splutter add the patra slices and toss. Transfer onto a serving plate, garnish with coconut and coriander leaves and serve hot.