"This pizza is all about the cheese, Provel, which is made only in St. Louis and can now be found for purchase online. A processed cheese that combines cheddar, Swiss and provolone, it has a texture akin to that of American cheese and a flavor not unlike that of smoked Gouda — and, for pizza lovers outside St. Louis, it may be an acquired taste. Because Provel gets very gooey in the oven, parbaking the crust before adding the sauce and cheese helps the crackerlike crust crisp up nicely...."