Sour Cream and Scallion Mashed Potatoes

My current favorite mashed potatoes.

10 large Idaho potatoes (7 pounds), peeled and quartered
5 garlic cloves, peeled
1 cup reduced-fat sour cream
1/2 cup milk
4 tablespoons unsalted butter, softened
7 scallions, white and light green parts, thinly sliced
salt
black pepper


Place the potatoes and garlic in a large pot and add enough water to cover. Bring to a boil and cook until tender, about 20 minutes. Drain the potatoes and garlic and return to the pot. Add the sour cream, milk, and butter and mash with a potato masher. Add scallions and stir gently to combine well. Season to taste with salt and pepper. Serve hot.