Heat up a sauce pan add in a tbsp butter add in black gram and cumin seeds let it splutter add in onion,saute it,now add mashed potatoes chilli powder, coriander powder, chat masala powder, combine well, add salt, saute it for 2-3 minutes add in chopped coriander leaves mix well keep aside.

Take a slice of bread apply butter spread potato filling, place one more bread on top, gently press it, add a tsp of butter to the pan place the bread sandwich,toast it both sides..do the same with rest of the bread slices...and it's done..enjoy with a cup of hot tea...