Peel the potatoes and cut them in 1-inch cubes. Place the potatoes in a pressure cooker with water to cover and a tablespoon of salt and cook over medium heat until tender, for about 5 minutes. You can also cook the potatoes in a saucepan, bring to boil and reduce to simmer until tender, for about 30 minutes.
Drain the potatoes and transfer them into the bowl of an electric mixer. Add the butter and milk and whip the potatoes to a smooth texture, about 5 minutes. You shouldn't see any lumps. If you do, keep mixing. Season with salt and pepper and serve immediately.
Pressure cookers save a ton of time in the kitchen. You can also cook the potatoes in a pot but the pressure cooker cuts the cook time of the potatoes from 30 minutes to 5 minutes!
Recipe adapted from Georgia Cooking in an Oklahoma Kitchen by Trisha Yearwood (c) Clarkson Potter 2008