Cheddar Garlic Stuffed Potatoes

Preheat oven to 400 °F. Cut off and discard top third of garlic and wrap remainder in foil. Prick potatoes with a fork and bake with garlic on middle rack of oven 45 minutes. Remove garlic to cool and continue baking potatoes until tender, about 20 minutes more. (Leave oven on.) Squeeze garlic cloves into a bowl and discard skins. Stir in butter, sour cream, and 1 cup Cheddar. Cutting lengthwise, remove top fourth of each potato and discard. Leaving 1/4-inch-thick shells, scoop flesh out of potatoes and add to cheese mixture. Mash with a fork to combine. Season with salt and pepper and divide among shells. Arrange potatoes in a small baking pan and sprinkle with remaining Cheddar, then bake until heated through, 15 to 20 minutes.