At a bustling counter inside Güerrín, a central Buenos Aires pizzeria, a young server in a red-and-white uniform dished out slices. Laid out before him was an abundance of thick, golden pizzas, their toppings a bright blend of green olives, red peppers and crispy melted cheese. The queue reached almost to the door, as he cut the portions with movements as lean and efficient as a juggler, the wedges disappearing in minutes.