Place the potatoes in a stockpot and fill with water to cover. Add 1 tablespoon salt and cook until the potatoes are tender, 30 minutes. Drain the potatoes and transfer to a large mixing bowl. Mash the potatoes with a masher (see Cook's Note). Add the cream, butter and 1/2 teaspoon each of salt and pepper and mix well. Add more salt, pepper and butter to taste.
Don't mash too much as you want the smashed potatoes to be chunky.