- 4 pounds red potatoes (about 8), halved
- kosher salt and black pepper
- 2 cups sour cream
- 1/2 cup milk
- 4 tablespoons unsalted butter
- 2 scallions, chopped
- Place the potatoes in a large pot.
- Add cold water to cover and bring to a boil.
- Add 2 teaspoons salt, reduce heat, and simmer until tender, 15 to 18 minutes.
- Drain the potatoes and return them to the pot.
- Add the sour cream, milk, butter, scallions, 1 teaspoon salt, and 1/4 teaspoon pepper and mash.
- Transfer to a heatproof bowl, cover, and set over a pot of simmering water to keep warm, up to 1 hour.