Set a large pot of water to boil, then add the peeled potatoes and half of the salt and cook for about 15 minutes, or until they are fork-tender. Then, drain and add the potatoes back to the pot.
Preheat your smoker to 225°F (107°C)
Add the rest of the salt, black pepper, garlic, butter, cream cheese, and half of the milk to the pot. Using a potato masher or a wooden spoon, mash the potatoes until they are smooth, adding more milk as necessary to get a perfect consistency.
Transfer your mashed potatoes to a 12-inch cast iron skillet and smoke the potatoes in the smoker, with the lid closed, for 1 hour.
Remove the mashed potatoes from the skillet, taste, and adjust seasonings if necessary. Garnish with fresh chives and additional melted butter, if desired.