Scrub and peel the potatoes. Dice into even 1/2" cubes to even out cooking time. 

Place in a large Dutch oven with just enough water to cover. 

Salt the water and bring to a boil. Cook, covered, for 15-20 minutes, or until a fork pierces the potatoes easily.

Drain the potatoes and return to the Dutch oven. 

Add the cream and using a blender or a masher, mash the potatoes.

 Add 2 tablespoons butter and mix until incorporated. 

Add more cream, if needed (starch may vary from potato to potato). 

Season with salt and pepper to taste and top with remaining 2 tablespoons of butter to entice friends and family into extra big spoonfuls.