Make-Ahead Mashed Potatoes

Ingredients

• 4 lb. medium Yukon Gold potatoes, scrubbed
• Kosher salt
• ⅔–1 cup heavy cream
• ⅔–1 cup whole milk
• 1¼ cups (2½ sticks) unsalted butter, cut into pieces
• ½ cup sour cream
• Freshly ground black pepper
• A potato ricer or food mill fitted with fine disk

Steps

1. Put 4 lb. scrubbed medium Yukon Gold potatoes in a large pot and cover with cold water by 1". Add a large handful of kosher salt so the water tastes briny, like the ocean, and bring to a boil. Reduce the heat and simmer for 30–40 minutes until very tender but not crumbly. Drain and return to the warm pot to dry off the heat.
2. Meanwhile, heat ⅔ cup heavy cream and ⅔ cup whole milk in a small saucepan over medium heat until just about to simmer. Reduce to low and keep warm until needed for the potatoes.
3. Pass the hot potatoes and 1¼ cups (2½ sticks) unsalted butter, cut into pieces, through a ricer into a large bowl to combine them quickly. Most skins should stay behind; pick out small pieces that get through if you want. Season generously with salt and mix with a potato masher until the butter is melted and combined.
4. Gradually fold in half the warm cream mixture with a spatula until combined, followed by ½ cup sour cream. Gradually add the remaining cream mixture until the desired consistency is reached; the potatoes thicken slightly as they sit. Taste and season with salt and freshly ground black pepper as desired.
5. Transfer to a baking dish or another shallow container and cool until the potatoes stop steaming. Cover and chill for up to 2 days.
6. To serve, put the refrigerated potatoes in a small pot with ⅓ cup heavy cream and ⅓ cup whole milk. Reheat over medium-low heat, stirring often but gently to prevent scorching.