In the U.S., many different cities and regions have their own local versions of pizza, but the two most famous are New York-style and Chicago-style pizza (also called deep-dish pizza). Chicago pizza is baked in a round pan similar to a pie pan—this is the “deep dish” that gives the pizza its other name. The buttery, rich dough is spread on the bottom of the oiled pan and also worked up the sides, and it is partially baked before toppings are added. It should be crispy, flaky, and rich.

Source: Pizza Chicago