Fill large pot with enough cold water to cover potatoes, stir in 2 tablespoons of salt and bring water to a boil. Cook until fork tender, about 40 minutes.
Drain in colander and transfer to bowl. Place pot back on stove and add cream and butter over low heat. Stir to combine, then add potatoes and turn off heat.
Crush potatoes using potato masher or wooden spoon until desired texture.