Place the potatoes and garlic in a large pot. Fill the pot with water and place over high heat. Bring to a boil and allow to cook until very tender, about 30 minutes. Drain the potatoes and garlic and place in a large mixing bowl. Add the butter. With an electric mixer, beat until smooth. Gradually beat in the warm half and half and sour cream. Season with salt and pepper and stir in the chopped chives or parsley. Return mixture to pot and heat through.
