Buttermilk Mashed Potatoes with Chives

• 3 lb. russet potatoes (4 to 6 medium), peeled and cut into 1-1/2- to 2-inch chunks
• Kosher salt
• 6 to 8 Tbs. unsalted butter, at room temperature, cut into 4 pieces
• 1 cup buttermilk, at room temperature
• 1/4 cup thinly sliced chives (1 small bunch)
• Freshly ground black pepper

Put the potatoes in a large saucepan and cover by an inch with cold water. Add 1-1/2 tsp. kosher salt. Bring to a simmer over medium heat, partially cover, and simmer until the potatoes are tender and easily pierced with a skewer, about 20 minutes. Drain, and return the potatoes to the saucepan. Put the pan over low heat, and shake or stir the potatoes until a floury film forms on the bottom of the pot, 1 to 2 minutes.

Using a ricer, food mill, or potato masher, mash the potatoes. Stir in the butter, 1 piece at a time, with a broad wooden spoon. Once the butter is thoroughly absorbed, add the buttermilk in three parts, stirring vigorously between additions. Add the chives, and season to taste with salt and pepper. Serve hot.