5 pounds russet potatoes, peeled and cut into 1-inch cubes; Kosher salt ; 4 tablespoons unsalted butter; 1 cup sour cream; ½ cup whole milk, plus more as needed; Directions.

Potatoes can be a bit sly. We’re used to buying them either piecemeal or by the bag, so when you step back to try and really understand what a pound looks like, it can be a bit puzzling. Not to ...