Peel potatoes and cut them into chunks. Cover potatoes with water and bring to a boil; salt water and boil 12 to 15 minutes until tender. Drain and return to hot pot.
While potatoes cook, heat a small skillet with a drizzle of extra-virgin olive oil over medium-high heat. Brown the bacon then drain and reserve.
Mash potatoes with bacon, sour cream, horseradish and pepper.
Recipe courtesy Rachael Ray, 2008