Today is National Sandwich Day, an annual celebration of the beloved food item named after the Earl of Sandwich. But it also turns out that the Jersey-style submarine sandwich is having a moment.

Quietly, in almost under the radar fashion, Manasquan-based Jersey Mike's Subs has become the fastest-growing restaurant chain in the nation for the past three years.

With $525 million in revenue in 2015, the chain ranked 81st on the list of the largest chains in the US -- just one spot (and $3 million) behind White Castle, according to Nation's Restaurant News. (Subway still tops the list with 33,000 stores worldwide.)

In the process, Jersey Mike's has taken the quintessential New Jersey sub shop experience and made it a nationwide hoagie habit.

The guy at the slicer cutting fresh meat. The oil and vinegar. The banter from behind the counter.

Even Californians -- with 200 stores in the Golden State alone -- are ordering by number and chowing down on their #13's (that's the classic Italian with ham, prosciuttini, salami and pepperoni) and their #2's (provolone, ham and cappacuolo).

"We've taken that taste profile across the country and it resonates everywhere,'' Jersey Mike's president Hoyt Jones tells me, seating at a table inside the Jersey Mike's location in Red Bank.

The company has doubled in size over the past three years, with 1,200 stores operating and another 500 in development. The chain added 197 new stores last year alone.

Jersey Mike's started like any one of the thousands of mom and pop sub shops on any main street in New Jersey.

Opening as Mike's Subs in Point Pleasant in 1956, the shop owner made a fateful hire in the summer of 1971 when he hired a local 14-year-old kid named Peter Cancro.

Cancro was not your typical teenage sandwich slinger. He soaked up the business like a soft roll meeting red wine vinegar.

Two years later, with a loan secured with help from his football coach, he bought the place and soon opened two more locations. By 1987, Cancro had changed the name to "Jersey Mike's" and began selling franchises.

Jersey Mikes's Subs CEO and founder Peter Cancro (left) stands with a customer outside the chain's original location in Point Pleasant. (photo courtesy of Jersey Mike's Subs)

"It's a Ray Kroc / Tom Monaghan type story,'' Jones said, comparing Cancro to the founders of McDonald's and Domino's Pizza.

The goal with each new location is to replicate the experience of the original Mike's in Point Pleasant. The top priority -- and what sets the chain apart, Jones says -- are the ingredients.

The roast beef is roasted on site in every store. Even if you're in California, the bread (also baked on site) is made with dough from Gutenplan's frozen dough in Middletown. And the meat is sliced to order, making the slicer -- referred to as the "quarterback" of each store's staff -- the star of the show.

For New Jerseyans, Jersey Mike's is a familiar taste. Fresh cold cuts piled on a fresh baked bun with drizzled with oil and vinegar and spices -- a blend Jersey Mike's refers to as "The Juice."

There's also the vibe and beach decor, lifted straight from the Jersey Shore location and duplicated in stores hundreds of miles from the nearest lifeguard stand.

The Jersey Mike's Subs location in Red Bank, NJ Oct. 31, 2016. (Brian Donohue | NJ Advance Media for nj.com)

The center of the growing empire remains the original Point Pleasant store, which is now the Jersey Mike's national training center, where new franchise owners come to learn how to prepare sandwiches and run their places like Cancro.

Like a baseball player trying to perfect his swing, trainees watch video tapes of themselves slicing and wrapping the subs to correct their technique. It's Hamburger University, Jersey sub style.

"Every one comes to Jersey,'' Jones said. "They learn -- it's mainly a discussion during the week about the different pieces of the business -- it's a cultural thing. So at the end of the week they know what made Peter tick and what makes him tick today, which is giving the consumer a high quality sub."

So how did Jersey Mike's do it?

Brian Todd, President and CEO of the Food Institute, a Saddle-River based food industry analytics firm, said the company was able to perfect its business model as a small local chain for several decades, then expand rapidly thanks to several trends

First, he said, is the arrival of millennials, a massive demographic bubble who spend an average of $2,921 a year eating out -- $300 more than the average baby boomer, Todd said. Jersey Mike's has also ridden a wave of shifting tastes toward fresher ingredients and a more authentic local feel compared to Subway and McDonald's, which lack a sense of connection to a specific locale.

And the company's use of social media marketing has also been stellar, he said.

"Right now, the atmosphere is right for them,'' Todd said.

Jones said Jersey Mike's could eventually expand to 10,000 locations.

But the growth underway is already enough to ensure that even if New Jerseyans travel far from home, we'll always be able to get a sub just like the ones we grew up eating.

Ask Camden County native Mark Belber.

He had been living in California for almost 12 years when he stumbled on a Jersey Mike's in Vacaville, between Sacramento and San Francisco. The taste reminded him of the subs he and his fellow boy scouts would make for camping trips and outings in the basement of United Methodist Church in Woodbury.

"It transported me right back to New Jersey,'' he said. "It's an amazing taste, when I grew up it's what we had. It's just amazing -- that flavor. It's not that hard when you think about it, it's oil and vinegar."

Brian Donohue may be reached at bdonohue@njadvancemedia.com Follow him on Twitter @briandonohue. Find NJ.com on Facebook.