The pizza's foundation is simple. It uses a thick layer of dough (made with olive oil and cornmeal) that is formed to a deep round pan and pulled up the sides. The pizza crust is then parbaked before the toppings are added to give it greater spring.
Parbaking is a cooking technique in which a bread or dough product is partially baked and then rapidly frozen or cooled. The raw dough is baked as if normal, but halted at about 80% of the normal cooking time, when it is rapidly cooled and frozen. The partial cooking kills the yeast in the bread mixture, and sets the internal structure of the proteins and starches (the spongy texture of the bread), so that it is now essentially cooked inside, but not so far as to have generated "crust" or other externally desirable qualities that are difficult to preserve once fully cooked.
The crust is then covered with cheese (generally sliced mozzarella) and covered with meats and/or vegetables such as Italian sausage, onions, and bell peppers. A sauce consisting of crushed or pureed tomatoes is then added. Usually this is topped with a grated cheese blend to add additional flavor. On the usual pizza, about a pound of cheese is added. Because of the amount of ingredients in this style of pizza, it is usually eaten with a knife and fork. It's quite messy to eat with your fingers.
In addition to Uno, additional famous deep-dish restaurants include Uno's companion restaurant Due, which was opened just down the block by Sewell in 1955. However, a year before, in 1954, The Original Gino's Pizza, located on Rush Street, opened its doors, and 12 years later in 1966, Gino's East opened. Other deep dish restaurants include Edwardo's, Connie's, Giordano's, Carmen's, Pizano's (which is owned by Rudy Malnati's son, Rudy Jr.), and Lou Malnati's (which was begun by another of Rudy Malnati's sons and is now run by his grandsons and has 26 Chicago area locations).
Chicago deep-dish pizza is famous throughout the world. Accordingly, many Chicago deep-dish pizza restaurants will ship their pizzas, partially baked, within the continental U.S.
In the mid-1970s, two Chicago chains, Nancy's, founded by Rocco Palese, and Giordano's began experimenting with deep dish pizza and created the stuffed pizza. Palese based his creation on his mother's recipe for scarciedda, an Italian Easter pie from his hometown of Potenza. A Chicago Magazine article featuring Giordano's stuffed pizza popularized the dish. Other pizzerias that make stuffed pizzas include Bacino's, Edwardo's and Carmen's. Most also make thin crust pizzas.
Stuffed pizzas are often even taller than deep-dish pizzas, but otherwise, it can be hard to see the difference until you cut into it. A stuffed pizza generally has much higher topping density than any other type of pizza. As with deep-dish pizza, a thin layer of dough forms a bowl in a high-sided pan and the toppings and cheese are added. Then, an additional layer of dough goes on top and is pressed to the sides of the bottom crust.
At this stage of the process, the thin dough top has a rounded, domed appearance. Pizza makers often puncture a small hole in the top of the "pizza lid" to allow air and steam to escape while cooking. This allows the pizza sauce to permeate through the pie. Pizza sauce is added to the top crust layer and the pizza is then baked.
Chicago pan pizza in Chicago is similar to the traditional deep-dish style pizza served in other areas of the country, and baked in a similar deep-sided pan, but its crust is quite thick -- a cross between the buttery crisp crust and focaccia. Toppings and cheese frequently go on the top of a pan pizza, rather than under the sauce as is traditionally the case with deep-dish and stuffed pizza. The placement of the cheese and toppings on top make the pan pizza variety similar to a thin-crust pizza with a thicker and larger crust.
In addition to Chicago-style deep-dish pizza, there is also a thin-crust pizza unique to Chicago, sometimes referred to as "flat pizza". The crust is thin and firm, usually with a crunchy texture, unlike a New York-style pizza, yet thick enough to be soft and doughy on the top.
Chicago style pizza has a rich and famous heritage and admirers from all over the world. If you're a pizza lover and you've never tried this type of pizza, be sure to give it a try, I'm absolutely convinced that you will love it!