Italian beef isn't just a Chicago sandwich. It's ingrained in the flavor of Chicago cuisine.
At least that's how the proprietor of Mr. Beef sees it.
Christopher Zucchero has made Mr. Beef his life's work, succeeding his father, who opened the preeminent Italian beef stand at 666 N. Orleans St.
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"Italian beef is truly what I believe to be Chicago's real root food," he told Fox News Digital in an interview from his Minnesota cabin just ahead of the start of the Democratic National Convention this week.
"You know, it's not pizza. It's not hot dogs. It really is Italian beef. It's something that we created. It's our thing, you know, like the Philly cheesesteak, or like pizza is to Connecticut or Rhode Island."
Here are five things to know about Mr. Beef and Chicago's culinary classic.
An "authentic traditional Italian beef sandwich," as Zucchero described it, is thinly sliced, comparable to roast beef, and "cooked in its own juices."
At Mr. Beef, Zucchero and his team create a gravy out of the cooking process, "which we then separate, and we make this kind of sandwich where we take the beef, we throw it in the gravy, we kind of swim the beef around in the gravy, [and] put it on a piece of French bread that's baked fresh daily in Chicago at a place called Liborio, one of the last of the bakeries – real, authentic Chicago bakeries – left in the city."
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Mr. Beef then uses a jardinière mix, like a muffuletta mix, "and we throw that on top of the sandwich," Zucchero said.
Add some sweet peppers "and that's your quintessential beef sandwich," said Zucchero. "And that's what we do there daily and have for the last 45 years."
The origins of Italian beef, Zucchero said, can be traced to the early 1900s when Italians immigrating to Chicago attended what's known as "peanut weddings."
Its name was coined "because that's what they had as appetizers — peanuts that they would break open and eat. And they would throw the peanut shells on the floor."
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Said Zucchero, "And they would have these big roasts for the actual dinner for the wedding, and then anything that wasn't eaten or finished by the time the wedding was over, they'd bring home.
"The next morning, they would bake fresh bread and make sandwiches, and they would take whatever was left of the roast and put it on there."
Zucchero took over operations from his father, Joseph Zucchero, who died last year at the age of 69. The son has worked there for the last 28 years, along with most of the same crew.
"I guess I've been kind of running it," Christopher Zucchero said.
Zucchero indicated that he often doesn't realize he's the boss, though.
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"I always looked at myself as just another employee there," he said. "I never looked at myself as I was running it. I was just — I'm Joe's son, you know. That was the only difference with me."
He added, "I still wash dishes. I'll clean the grease trap. I'll go sweep the parking lot. I'll throw the garbage out. I mean, we all do that. That's my big thing. Nobody has a position. Everybody does everything."
Italian beef has found a broader popularity with the hit FX series "The Bear," which is filmed in Chicago's River North neighborhood, home to Mr. Beef.
Its dining room was used for the pilot episode before a replica was built for filming, but Mr. Beef continues to have a prominent role in the series.
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The central character in "The Bear" is inspired by the real-life Zucchero.
"That's what my friend said," Zucchero said. "I didn't say that."
Zucchero's friend is series creator Christopher Storer, whom he's known since kindergarten.
"I never accept that, and I think it's wonderful," Zucchero said of being Storer's muse.
"He said that, and I love that kid with all my heart. He knows that already. I'm very honored by all of it. But it's weird for me to say that."
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Rather, Zucchero said he believes Mr. Beef set the aesthetic for the series.
"Actually, I have to say, I feel like the restaurant itself is obviously the inspiration, and it's almost like a 12th character on that show. It really is," Zucchero said. "Or at least now it feels like that."
Not that Zucchero watches it, he said.
"I get real creeped out when I see anything related to Mr. Beef or me on TV or whatever," he told Fox News Digital.
"So, it would be a nightmare for me to watch that show, because even if they just pan to the crown molding in the restaurant, you know, it just it bothers me. It just bothers me. So, no, I've never watched it fully."
But Zucchero said he's happy for Storer. "I've always been a big supporter of him."
Zucchero couldn't speak as to why everyone loves Mr. Beef so much.
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But a representative for Chicago's tourism arm had this to say about the 45-year-old establishment.
"Mr. Beef exemplifies classic Chicago comfort food and is a quintessential example of the Chicago style that makes us such an appealing destination," Lisa Nucci, chief marketing officer at Choose Chicago, said in a statement to Fox News Digital.
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"It's truly hearty, delicious and totally unpretentious. And now, it's the inspiration for one of the biggest hit TV shows of the last few years."
Said Zucchero, "It's really a Chicago thing. It's our thing," he said.
