Take a one bowl of water then cut in potatoes with skin in small cubes in water.
Then wash potato two or three tym.
Take a all masala get inone bowl mix well.
Take a wok add mustard oil,oil smoke then add all masala then masala color change in blakish then add potatoes mix and covered with lid.
After 20 minutes potatoes r soft and saute in few seconds for high flame.
Serve Aloo posto. (bengali dish)