Peel, grate and squeeze potato as much as possible using muslin cloth.
Take all the ingredients except butter in a bowl. Mix well.
Heat nonstick pan. Add butter. Let it melt.
Spoon the potato cheese mixture into the pan and press it gently into a disc shapes using spatula. Repeat the process with remaining mixture. At a time 3-4 rostis can be shallow fried.
Shallow fry rosti from both the sides over a low flame for 8-10minutes until crisp and brown.
Serve hot with tomato ketchup.
