01 -
3 pounds potatoes (russet or Yukon Gold), peeled and chunked.
02 -
3 garlic cloves.
03 -
1/2 cup (1 stick) unsalted butter, plus more for serving.
04 -
1 cup whole milk.
05 -
1 1/2 teaspoons sea salt, plus more for cooking water.
06 -
Fresh ground black pepper.
07 -
1/4 to 1/2 cup sour cream (optional).
08 -
Chopped fresh chives for garnish.