When Danny Meyer’s humble(ish) Shack Shake first set out, the restaurateur didn’t anticipate it to grow from its Madison Square Park roots. However, years passed, burger sales soared and the Shack celebrated its 100th location in the Seaport this week.

This is all well and good for anyone looking for a solid cheeseburger that tastes like it hit the grill fresh and comes with an smorgasbord of side options, and alternatives (including a “veggie burger” made up of two fried mushroom caps stuffed with cheese — drool). But in a saturated fast casual burger market, how does Shake Shack still stand out?

Well, there are a few ways — one, they’re consistent. The burger I have in Boston tastes exactly like the burger I have in New York. This is the same concept keeping McDonald’s — and their (almost always) consistently excellent fries—  afloat. Two, they know how to work the system: the social media system. Shake Shack isn’t afraid to bow down to the chefs they know are greater than, say, the burger mavens they hire to work behind their counters. And they've got the Instagram likes to prove it. 

Meyers and his team asked April Bloomfield (The Spotted Pig, The Breslin), Daniel Humm (Eleven Madison Park, The Nomad), and David Chang (Momofuku, Ma Peche) to improve upon their burger for a series of culinary collaborations to celebrate the company’s 10th anniversary. And for their 100th Shack, culinary director Mark Rosati asked chefs Jamie Bissonnette and Ken Oringer (Toro, Coppa and most recently Little Donkey) to create a burger all their own.

The chefs and co-owners met Rosati years back when Bissonnette made his way into a newly opened Shack in Philadelphia. When the first Boston area location opened in Chestnut Hill, Rosati made a point to visit Coppa, which made such an impact that when it came time to open the Seaport location, he knew who to call.

The deli grinders (don’t call them “subs” or “hoagies”) of Bissonnette's Connecticut upbringing inspired the Coppa Burger, which is available in all five Boston locations through Sunday. It features a crispy-edged all-natural Angus beef patty, with an even crispier slice of griddled, delightfully salty mortadella on top. A slice of gentled melted provolone topped with chopped tangy cherry peppers, bottomed out with sweet soft caramelized onions, with the key combo of shredded lettuce and mayonnaise rounding out a squishy, melty umami that's difficult to forget and impossible to share.