Fill a medium size saucepan half full of water, and add a pinch of salt. Bring to a boil. Add potatoes to pot; the water should cover the potatoes. Simmer for 10 minutes, or until potatoes are easily pierced by a fork. Drain.
Transfer potatoes to a large mixing bowl. Add butter or margarine and milk, and mash with a potato masher. When well mashed, whip for a minute or two with an electric mixer set on medium speed.