Put the potatoes in a saucepan and add enough water to cover generously. Salt the water, bring to a slow simmer over medium heat, and cook until the potatoes are tender when poked with a fork, 15 to 20 minutes.
Meanwhile, combine the cream and milk in a small saucepan and bring to a simmer. Keep warm until ready to mix with the potatoes.
Drain the potatoes, and push them through a ricer into a mixing bowl. Begin whipping the potatoes ¿ either in a stand mixer fitted with the whisk attachment or with a handheld mixer ¿ adding the butter as you go. When the butter has melted, gradually add three-quarters of the hot cream mixture, whipping until the potatoes are soft and fluffy. Add 1/2 teaspoon salt and the pepper, and then any additional cream mixture as needed for the potatoes to achieve the texture of stiffly whipped cream. Serve immediately, or cover and set over a double boiler to keep warm.
Adapted from "The New Midwestern Table" by Amy Thielen (c) Clarkson Potter, 2013. Provided courtesy of Amy Thielen. All rights reserved.