Ingredients

Serves 4 to 6

　　1 garlic head, unpeeled

　　2 1/2 pounds red potatoes (about 16 medium)

　　2 tablespoons unsalted butter, softened

　　1/4 cup sour cream

　　1/4 cup buttermilk

　　1 tablespoon chopped fresh chives

　　2 tablespoons olive oil

　　1/2 cup freshly grated Parmesan (about 1 1/2 ounces)

　　a pinch freshly ground white pepper, or to taste

　　

Step 1

Preheat oven to 400°F.

　　

Step 2

Cut top 1/4 inch off garlic head and wrap head in foil. Roast garlic 40 to 50 minutes, or until very soft, and cool. Squeeze roasted garlic from head and reserve.

　　

Step 3

In a 4-quart saucepan cover potatoes with water by 2 inches and simmer until very tender, about 30 minutes. Drain potatoes in a colander (do not peel). Transfer potatoes while still hot to a large bowl and add butter. With an electric mixer on low speed mash slightly. Beat in sour cream, buttermilk, chives, and oil until combined well. Add Parmesan, reserved garlic, pepper, and salt to taste, beating until smooth.