Place the potatoes directly on the grate in your preheated smoker. Smoke for an hour at 225°F.
Wrap the potatoes in foil along with two tablespoons of the butter and place them back in the smoker.
Allow the smoker to get up to 250°-275°F. Continue to cook for about another 90 minutes or until the internal temperature of the potatoes reaches 205°F.
Transfer the potatoes to a large bowl and mash with a hand masher. Add the remaining ingredients and season to taste.