Place the potatoes in a large pot and add cold water to completely cover. Add the salt and bring to a boil. Cook for about 15 minutes or until the potatoes are easily pierced with a paring knife.
Drain the potatoes. When they are cool enough to handle—but still hot—slip them from their skins and discard the skins.
In a small pot, combine the cream and butter and bring to a boil.
Return the potatoes to the large pot and mash with a potato masher. Pour in the hot cream mixture in four increments and, each time, mix until combined. Once the potatoes are smooth, add the pepper and salt to taste. Serve immediately.
