Take a big bowl,take boiled potatoes,mashed it well,mix onion,green chilli,salt,red chilli powder,chat masala,amchur powder and make a fine paste.

Take a slice of bread and spread green sauce and red sauce on another slice.Now spread our potao paste on one slice and covered with another slice.

Now take a pan or tawa,heat it and take our sandwich,apply butter or ghee both side,cook it till brown and serve it with red sauce or green sauce.