Since the late ’80s, New York City has had a secret: a sweet, creamy, frozen dairy dessert that won’t mess up a model’s diet, or anyone else’s for that matter.

The secret has gotten out, however, as Tasti D-Lite stores have opened in places as close to the Big Apple as New Jersey and Connecticut, and as far away as Texas, California, and Arizona. And international dessert lovers are trying Tasti D-Lite these days, too, as the concept has spread to Mexico and Dubai.

“Our goal is to open 50 more domestically and 14 internationally in 2011,” says Tasti D-Lite CEO Jim Amos. “But we think we will do even better than that.”

Tasti D-Lite was founded in 1987 in the kitchen of a New York City woman working with her food technologist father. Her goal was to create a delicious but guilt-free frozen dessert.

Sold by independent licensee wholesalers for years throughout New York, Tasti D-Lite grew in popularity. In February 2007, a New York–based private equity firm, SPG Partners LLC, acquired the company and Amos, one of the firm’s operating partners, was named CEO. The company began awarding franchises in early 2008.

Amos, who grew Mail Boxes Etc. to more than 4,000 units before selling it to UPS in 2001, already had experience in frozen desserts. He was the former CEO of Brice Foods, whose I Can’t Believe It’s Yogurt! brand grew to more than 1,300 domestic and international locations during his tenure before being sold to Yogen Früz in 1996.

“The core product of Tasti D-Lite is what separates us from everyone else out there in the $22 billion frozen dessert industry,” Amos says. “The product itself tastes great and it grew for 20 years in the toughest retail market in the world. It’s lower in calories, lower in sugar and carbs, and higher in protein. It’s made from natural ingredients and has no artificial ingredients. It’s got mouthfeel, taste, and creaminess.”

Amos, who operates the New York–born Tasti D-Lite company from Nashville, says what SPG purchased was the proprietary formula for Tasti D-Lite.

“We added everything else,” Amos says. “We created the franchise program and the operating manuals. We looked at everything from the logo to the store footprint. We did focus groups all over the U.S. and then began targeting cities where we wanted to grow.”

Tasti D-Lite comes in 100 flavors, with customers usually being able to choose among four to six flavors each day, depending on which location they visit. Flavors range from French Vanilla and Coffee Toffee to Pomegranate and Double Berry. For customers who crave the tangy flavor of frozen yogurt, several Tart ’n Tasti flavors were created, including Acai Tart ’n Tasti and Mango Tart ’n Tasti.

Tasti D-Lite is served in cups, cones, smoothies, shakes, and sundaes. Blended frozen coffee and tea were recently added to the menu, and customers can also add one of eight nutritious Tasti Shots to any of the blended products. These include antioxidant, energy, immune support, multivitamin, probiotics, protein blend, relaxing blend, and trim and fit shots.

Tasti D-Lite patrons don’t all indulge inside the store. Take-home Tasti cakes, pies, and novelties are available, as is Tasti D-Lite by the pint or quart.

Depending on the flavor, Tasti D-Lite has between 70 and 100 calories per four-fluid-ounce serving, with most flavors having 80 calories or less, 1.5 grams of fat, and 14 grams of carbs.

The prototype Tasti D-Lite unit is between 1,000 and 1,200 square feet with seating for 20–30 guests, but the concept is not limited to traditional real estate. It’s available through kiosks, mobile units, and outlets as small as 200 square feet for college campuses, airports, and grocery and convenience stores. A self-serve hybrid location has also been developed, providing service for customers ordering smoothies and other blended items as well as a weigh-and-pay method for cups and cones.

While a few beach locations operate seasonally, most Tasti D-Lite stores are open year-round—a testament to their loyal fans, Amos says.

“One thing I found interesting when I was doing my due diligence on the concept was that I saw people in line at a Tasti D-Lite in New York in January, and it was only 18 degrees outside,” he says. “I thought, ‘This is nuts,’ but customers were just unwilling to give up their Tasti, no matter the weather.”

These loyal fans of Tasti D-Lite have proved to be the concept’s best promoters, especially through social media.

“Tasti was one of the first companies out there to align its loyalty program with Twitter,” Amos says. “When someone comes into the system and uses a loyalty card, it gets tweeted. So when Taylor Swift came in to our Nashville store, it was tweeted to about 850,000 people.”

The celebrity factor has been big for Tasti D-Lite, whose fans include actresses and supermodels looking for a low-calorie indulgence. But, Amos reiterates, despite Tasti D-Lite’s unsolicited exposure on TV shows like Sex in the City and The Apprentice, its success is more dependent on how the product tastes than who is tasting it.

“This business rises and falls on the taste of the product,” he says. “Tasti D-Lite delivers a taste and mouthfeel that no one else can deliver.”