With rivulets of broth and tendrils of provolone spilling from its sides, an italian-beef sandwich seems like the pinnacle of decadence. In fact, the dish was probably born of thriftiness. At big Italian American weddings in Depression-era Chicago, the story goes, cooks would try to stretch out roast beef by slicing it ultra-thin and stewing it in stock seasoned with fistfuls of garlic, oregano, and pepper.

Today, there are more than 600 spots to find italian beef in Illinois alone, according to the fanatics at ItalianBeef.com—about as many as reside in all the other states combined. But though many of these craftspeople put their own special stamp on the sandwich, there’s an essential anatomy that can generally be counted upon to transcend variation. Here’s what you’re getting when you order italian beef:

Meat

The core element of italian beef is, of course, beef. The specific cut can vary, but since the meat typically undergoes a lengthy preparation process before hitting the roll—roasted for hours, sliced paper-thin, and simmered in juices—the tougher, less-expensive roasts like top or bottom round are popular choices. At the legendary Al’s #1 Italian Beef in Chicago, it’s top sirloin they’re sending through the slicer.

Bread

Given that italian beef is generally covered or even dunked in a meaty jus-like broth, it needs a roll with some wherewithal. Italian rolls are the default choice thanks to their crusty exteriors and phenomenal powers of absorption.

Cheese

The classic italian beef sandwich is a dairy-free affair, but many people find that, like almost everything else, it benefits from a few slices of cheese. In those cases, it’s typically mozzarella or provolone that gets the nod—both cheeses that feature high meltability, mild flavor, and Italian heritage.

Toppings

There are generally only two options here: peppers or peppers. Green peppers (you can just say “sweet” at most Chicago beef counters) and the blend of pickled hot peppers, carrots, celery, and spices known as giardiniera (or simply “hot”) reign supreme among beef condiments, perhaps because of their knack for complementing the seasoning of the beef itself.

Juices

Whether you call it juice, jus, or gravy, the rich, meat-infused liquid that italian beef simmers in is as much a defining element of the sandwich as the beef itself. Of course, some volume of juice will inevitably accompany the beef as it’s piled onto the roll; if you can handle a supremely sloppy sandwich, you can also get more juice ladled on top or applied via a dunk in the broth pan for a “wet” or “dipped” version.

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