Rub off the excess papery skin from garlic without separating the cloves. Slice the tip off the head, exposing the ends of the cloves. Place the garlic on a piece of foil, drizzle with oil, and wrap into a package. Roast until the garlic is golden brown and soft, about 45 minutes. When cool enough to handle, squeeze the cloves and any oil left in the foil into a small bowl.
Meanwhile, combine potatoes and turnips in a large pot and add enough cold water to cover. Bring to a boil over medium-high heat. Reduce heat to medium-low, cover, and cook until tender, about 20 minutes. Drain.
Return the potatoes and turnips to the pan and place over medium-low heat. Add the roasted garlic and mash with a potato masher to desired consistency. Stir in milk, Parmesan, thyme, chives, butter, salt, and pepper.
Recipe courtesy of Eating WellSource: Diabetic Living Magazine, Winter 2020