[2][3][4][5][6][7] Chicago-style deep-dish pizza was invented at Pizzeria Uno in Chicago, founded by Ike Sewell and Richard Riccardo in 1943.

[8][9][10] Riccardo's original recipe for a pizza cooked in a pie pan or cake tin was published in 1945 and included a dough made with scalded milk, butter, and sugar.

[11] The restaurant's cook Alice Mae Redmond later adjusted the recipe to be made with water and olive oil and a "secret dough conditioner" to make it stretch better.

[33][34] In response, Technomics food industry researcher Darren Tristano questioned GrubHub's conclusion on the basis of the delivery service's user demographics, saying that its younger users can not afford deep dish pizza, while NPR noted that the data would not include information on two particular deep-dish chains (though with just 20 restaurants in the city of 2.7 million) that are not on GrubHub.

[33] The typical toppings commonly found on pizzas in most of North America (such as sausage, pepperoni, onions, and mushrooms) are also standards in Chicago-area pizzerias.