It's Curious City, where we take your questions about Chicago and the region, and investigate, report, explore, from WBEZ.

Hey, I'm Curious City reporter Monica Eng. And I'm her editor, Jessica Popovac. A few weeks ago, we answered a long-time Chicago cheeseburger mystery.

You see, all over the south side, there are these food joints named Nickies.

And while they don't seem to be related to each other, they all serve up this same specific double cheeseburger with grilled onions.

And they call it the big baby.

Our question asker, Connor McNamara, wanted to know where Nicky's and the Big Baby all started,

and we pretty much answered his question.

But we're back again, because since our original story aired last month, we got some shocking

and important new information, plus an amazing interview.

But first, if you've never had a big baby, let me tell you, it's a big deal.

And the purists say it's got to be stacked like this.

Bun, mustard, ketchup, pickle, patty, cheese, patty, grilled onions under a sesame seed bun.

The scrumptious combo has even impressed fancy Chicago Tribune food writer Louisa Chu.

She argues that the big baby should be Chicago's official burger.

We have Chicago-style hot dogs, Chicago-style pizza, but not one single Chicago style burger.

But absolutely, it should be the Chicago style burger.

But our search for the true origins of this big baby, it took some real twists and turns.

First, we went to one Nickies out in Gage Park.

They said they invented it to compete with the Big Mac in the late

60s. But then we went to another Nickies out by Midway. The owner there was a guy named

Angelo. He claimed his place was the first to serve the big baby two years earlier.

Angelo says his dad bought the restaurant, complete with the big baby from a Greek man named Nikki Vigenus.

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