The tang of sour cream gives the illusion that this recipe is not as rich as the cream, butter, and milk would imply.
Ingredients
3 pounds russet potatoes, peeled, cut into 2" pieces
1 pound Yukon Gold potatoes, peeled, cut into 2" pieces
Kosher salt
1 cup heavy cream
1 cup whole milk
1/2 cup (1 stick) unsalted butter; plus more for serving (optional)
Freshly ground black pepper
1/2 cup sour cream
Special equipment: A potato ricer
Directions
Place potatoes in a large pot and cover with cold water by 2". Generously season with salt and bring to a boil. Reduce heat and simmer until tender, 10–15 minutes. Drain and transfer potatoes to a baking sheet; let stand until dry, 10–15 minutes. Set pot aside.
Meanwhile, heat cream, milk, and butter in a medium saucepan over medium heat; season with salt and pepper.
Pass potatoes through ricer into reserved pot. Mix in warm milk mixture, then sour cream; season with salt. Serve topped with pepper and more butter, if desired.
DO AHEAD: Potatoes can be made 5 hours ahead. Cover and chill. Reheat gently, adding more milk to loosen as needed.
