A requirement of any visit to Chicago is eating at least one slice of deep dish pizza in the city that perfected it. Deep dish pizza quickly became a Chicago staple after Ike Sewell and Ric Riccardo opened the first Pizzeria Uno in 1943 and served a hearty new style of pizza constructed in a high-rimmed cake pan. The yeast crust was tender and flakey, like a pastry, and the cheese was layered under the sauce so that it wouldn’t burn in a hot oven for the long cooking time.