4 lb yukon gold potatoes peeled cut into 2" pieces
6 large garlic clove peeled
1 Tbsp kosher salt divided plus more
1.3 cups milk whole
4 thyme sprigs
0.8 cup butter unsalted divided ()
0.8 tsp pepper black freshly ground plus more
0.5 cup cream sour
Equipment
bowl
sauce pan
knife
pot
stove
potato ricer
Directions
Cover 4 lb. Yukon Gold potatoes, peeled, cut into 2" pieces, 6 large garlic cloves, peeled, and 1 Tbsp. Diamond Crystal or 1¾ tsp. Morton kosher salt with cold water in a large pot. Bring to a low boil on the stovetop over high heat, then reduce heat and simmer (do not boil) until potatoes are very tender when pierced with the tip of a paring knife but not falling apart, 20–25 minutes.
Meanwhile, heat 1¼ cups whole milk, 4 thyme sprigs, and ¾ cup (1½ sticks) unsalted butter in a small saucepan over medium, stirring, until butter is melted.
Remove from heat; set aside.
Drain boiled potatoes and garlic; return to pot. Toss over low heat until moisture evaporates, 1–2 minutes. Using potato ricer or food mill, immediately press potatoes and garlic into a large bowl (do not let cool).
Discard thyme from warm milk mixture and gradually stir into hot potatoes, reserving about ½ cup if you plan to make in advance (see Do Ahead). Season with 2 tsp. Diamond Crystal or 1¼ tsp. Morton kosher salt and ¾ tsp. freshly ground black pepper. Fold in ½ cup sour cream and stir with a spoon until incorporated and very smooth (do not overmix or potatoes will become gummy). Taste and adjust seasonings.
Serve topped with remaining 2 Tbsp. unsalted butter and more pepper.
Do Ahead: Mashed potatoes can be made 2 hours ahead; cover and store at room temperature. Or chill, covered, up to 8 hours; reheat over medium with reserved ½ cup milk mixture, rewarmed to melt butter.
Editor's note: This recipe was first printed November 201
