Place potatoes in a large heavy pot and cover with cold salted water. Bring to a boil over high heat. Reduce heat to low and simmer, partially covered, until tender, 10 to 15 minutes.Advertisement
Drain the potatoes and return to the pot. Off the heat, mash potatoes, adding enough hot broth to make a smooth puree. Stir in sour cream and season with salt and pepper.
To make ahead: Keep the potatoes warm, covered with wax paper, over a pan of barely simmering water for up to 1 hour.
2 1/2 starch