Deep-dish pizza in Chicago, USA: The pizza you must try before you die

This is an unusual story with strange ingredients: intrigue, passion, criminality – and pizza. Where better to start, then, than Gino's East, five minutes' walk from Chicago's mighty Michigan Avenue and a key stop-off in the culinary search for a dish synonymous with America's "second city"?

Though Gino's East has been serving deep-dish pizza since 1966, it didn't invent it. That honour is attributed to Pizzeria Uno, on the near North Side, which sold its first deep-dish pizza in 1943.

Yet who came up with the idea? Was it Ike Sewell, Pizzeria Uno's owner? Business partner, Ric Riccardo? Or original pizza chef, Ray Malnati? Thin crust pizzas, of course, were introduced to the US along with the waves of Italian migrants who flooded cities such as Chicago in the 19th and 20th centuries. Such Neapolitan-style pizzas were enjoyed by the city's most famous 20th century identity – Prohibition-era gangster Alphonse "Scarface" Capone. But this new deep-dish version was a genuine American creation.

What makes it so different? With perfect timing, our waitress Michelle brings out the lunchtime 12-inch pepperoni we'd ordered 40 minutes earlier (it can take up to an hour to deliver a deep-dish pizza). It's huge: more like a soggy open pie.

Trade secrets are strictly protected. But as Michelle carves it into thick, gooey slices, she says: "What sets us apart is the crust. We're known for our golden crust. Deep pan pizzas usually have a white crust."

We're all familiar with how thin crust pizzas are made. But the Chicago version is cooked in a deep metal "cake-pan-like" container and baked much longer. Precise methods vary but basically the pan is coated in olive oil, then topped with a dough of white and semolina flour which lines the bottom and sides of the pan. The oil fries the outside of the crust, ideally to a golden brown.

Filling layers arrive in reverse order to a "normal" pizza. First comes the cheese (Wisconsin mozzarella), then the meat and/or vegetables and finally crushed tomatoes. (The liquid keeps the cheese from burning while the other flavours meld.) Each slice oozes stringy cheese, spicy pepperoni and a rich tomato sauce that my fellow diners soak up with the ample amounts of crisp pastry.

To be honest, I'm the odd one out. Even here at Gino's East, I find deep-dish pizza a dish everyone should try once – but only in Chicago. The restaurant is a slice of authentic Chicago. Critics complain it's a just a bar with food and that's accurate. But on this Saturday lunchtime, multiple screens show college football action. There's a great range of draught craft beers. And the walls are covered in 50 years' worth of graffiti scrawled by satisfied customers. Some evenings there's a stage for emerging comedians (patrons are given tomatoes to pelt the hapless stand-ups). Meanwhile, for $US20, visit the professional Comedy Club upstairs (rumour has it Dan Ackroyd, of the Blues Brothers, performed here).