American pizza often has vegetable oil or shortening (often, but not always, olive oil) mixed into the dough; this is not as common in Italian recipes (for example, the pizza dough recipe in the influential Italian cookbook Il cucchiaio d'argento does not use oil). This can range from a small amount in relatively lean doughs, such as New York style, to a very large amount in some recipes for Chicago-style deep-dish dough.