Joseph Park did his cheesesteak research before opening his Baltimore sub shop. That research, which mostly involved following what cheesesteak fans said on Facebook, told him Cooper Sharp is the way to go.

Cheesesteaks are having a moment in Baltimore, with new restaurants popping up everywhere to serve Philadelphia’s signature dish. Their rise could threaten the longstanding dominance of Baltimore’s other favorite sandwich: the Italian cold cut sub.

At Subplicity, Park’s new Riverside sub shop, the Italian cold cut and cheesesteak are “fighting for top spot,” he said. Customers sometimes order cheesesteaks at 9 a.m., when the restaurant opens on Fridays and Saturdays. “It’s never too early or too late for a cheesesteak,” Park said.

Elkridge’s Cheesesteak & Co. has garnered long lines and major social media hype since opening last year, while Catonsville food truck 5th & Steaks has developed its own cult following. Even well-established restaurants are getting newfound attention for their cheesesteaks — places like Frank’s Pizza & Pasta, where the sandwiches got a rave review from Barstool Sports’ Dave Portnoy last year.

One thing all these places have in common? They offer Cooper Sharp. The white American cheese is the preferred brand used by “elite cheesesteak restaurants” in Philadelphia, Park said, and increasingly, customers in Baltimore ask about it by name. He can see why. Combining the sharp and nutty flavor of aged cheese with the “thicker meltier-ness” of processed cheese, “it has a much nicer ‘cheese pull’” than alternatives, Park said. “That’s the terminology people use nowadays on social media.”

When Park first opened Subplicity, he initially had trouble finding a local distributor for Cooper Sharp, so he drove to Harrisburg, Pennsylvania, to load up on cases. “I went through almost 200 pounds of Cooper Sharp cheese in a month,” he said.

While some Philadelphians prefer cheesesteaks with Cheez Whiz, provolone or American, Cooper Sharp is steadily gaining ground as the one ingredient that can make or break a cheesesteak — a hallmark of authenticity that sets the real thing apart from imitators. In a 2023 interview, Oscar nominee and Philadelphia suburb native Bradley Cooper (no relation to the cheese) defined a cheesesteak as having homemade, hollowed-out bread, sliced ribeye, caramelized onions and Cooper Sharp cheese. The latter was obviously on the menu when he opened Danny & Coop’s, his own New York City cheesesteak shop, late last year.

“That really has helped us,” said Michelle Spoerl, brand manager for Cooper cheese, a subsidiary of Wisconsin-based Schreiber Foods. She said that sales have grown 142% nationally over the past decade. She’s confident that that number will continue to grow, estimating that within the next four years, Cooper cheese will be featured on nearly 25% of all restaurant menus in the U.S.

In a way, Cooper Sharp can be seen as analogous to Maryland’s own Old Bay seasoning: a longstanding and beloved local brand that’s managed to help leverage its users’ loyal following into viral fame. Restaurant owners are responding in kind. “We get inquiries on our website almost every day, if not multiple times a day, asking about Cooper and how to get it on menus,” Spoerl said.

Despite historically high beef prices, the cheesesteak momentum seems to be showing no sign of slowing. This week, developers announced that a new branch of Pennsylvania’s Geno’s Steaks will bring Philly-style cheesesteaks to the Inner Harbor. Customers can select from a number of cheeses there: American, provolone, Cheez Whiz and, of course, Cooper Sharp.

But Spoerl stresses that their cheese isn’t just good on cheesesteaks. The same way Old Bay fans crave the seafood seasoning on everything from chips to ice cream, Cooper Sharp advocates recommend using it in macaroni and cheese, omelets and dips. “We’ve even seen some people put it in a dessert,” Spoerl said. “That sharp flavor profile is like a cheddar, and it pairs really well with apples.”

Just ask Evan Weinstein. The Underground Pizza owner recently began incorporating Cooper Sharp in the restaurant’s cheesesteak pizza and macaroni and cheese. About a week ago, he melted some and poured it into a fountain outside Underground Pizza’s branch near the Inner Harbor, using it to dip everything from French fries to chicken wings.

“It was delicious,” he said.