Put the potatoes in a large saucepan and cover w/ salted water. Bring to a boil, then reduce heat to medium and cook, covered, until tender, 15 to 20 minutes. Drain, then return the potatoes to the pot. (If you want you can turn the heat on low and carefully dry the potatoes for a minute or two, shaking the potatoes as needed) Add the butter and stir and mash until it melts completely. Add the milk and stir to mix. Season with salt and pepper and serve hot.