– With a $20 ice cream maker and a hunger for a more healthful indulgence, Los Angeles lawyer Justin Woolverton concocted a dessert that quickly developed a cultlike following.

A few years later, his line of light ice cream, called Halo Top, has exploded into surprising market dominance. Halo Top recently bested stalwarts Ben & Jerry’s and Haagen-Dazs for the top sales spot in its niche — grocery store ice cream pints.

“I thought, ‘This is really good. I’ll bet others will like it, too,’ ” Woolverton said.

Halo Top’s appeal is simple: a no-shame pint of low-sugar, high-protein ice cream with just 240 to 360 calories for the entire carton. Vanilla, at the low end, compares with 1,000 calories for a Haagen-Dazs or Ben & Jerry’s pint.

The gold foil that seals each Halo Top carton instructs “Save the bowl” or “Stop when you hit the bottom” — a nod to the way many fans consume the product.

That’s how budding YouTube personality Travis Stewart eats Halo Top.

“No one wants to have a few bites and put it back in the freezer,” said Stewart, a nutrition adviser by night, with his “Travis S” channel approaching 100,000 subscribers. “You can eat the whole pint without feeling any guilt.”

Halo Top’s push to become America’s bestselling grocery store pint accelerated in May, according to market research firm IRI Worldwide.

It closed the gap with leaders Ben & Jerry’s and Haagen-Dazs the next month and landed the top spot in July. For the 12 weeks that ended Aug. 6, IRI said, Halo Top had sales of $86.9 million, compared with $83.3 million for Ben & Jerry’s and $78.6 million for Haagen-Dazs.

To be fair, Halo Top rules just one supermarket category, not counting sales of sherbet or gelato or sizes other than pints. Still, experts consider the conquest a major achievement.

“It didn’t happen just once; it’s sustained. It’s a remarkable story,” said John Crawford, vice president of the western dairy region for Chicago-based IRI. “It’s crazy that someone can just come into an established industry and do this.”

Although Woolverton’s first ice cream attempt convinced him that others might buy it, there was a huge financial hurdle. Woolverton was already dragging around $350,000 in law school loans when he decided to fund his business using the good credit he built during four years at the law firm Latham & Watkins.

Woolverton said he was ready for a change. His work there hadn’t turned into one of the John Grisham novels that had inspired his legal career.

“It took me a year to figure out how to really make ice cream,” Woolverton said. “I had a good $150,000 in credit cards just to rack up. I mean, it was headfirst. It was a risk.”

A lawsuit forced a name change from the original Eden Creamery to Halo Top, ultimately leading to a better-looking brand, Woolverton said.

In 2012, Halo Top carved out shelf space in Sprouts, Erewhon and Whole Foods in a cold-call process.

As he landed the new accounts, fresh pressures developed, such as a longer supply and distribution chain. There were also formulation problems to rectify.

“As it sits and goes through truck after truck and different altitudes and all that,” Woolverton said, “sometimes it didn’t hold up well.”

Coming up with a longer-lasting formula took Woolverton to Cal Poly San Luis Obispo’s Dairy Innovation Institute.

“The ice cream came out better, more resilient,” Woolverton said.

Meanwhile, ice cream manufacturers told Woolverton his formula, with so much protein in it, was too thick to safely run through production pipes.

When he found a contractor willing to give his formula a shot, “sure enough, it does exactly what they warned us it would do,” Woolverton recounted.

Woolverton fiddled with the formula once more. Fortunately, the ice cream maker was willing to let the fledging business try again, as long as Woolverton agreed to pay for anything that broke.

“We were like, ‘Of course, that’s fair,’ ” he said. “It worked finally.”

The company has stuck close to its frugal beginnings, and the 38-year-old fitness buff sees no reason to change. There’s no fancy headquarters, just a low-rent co-working space in L.A.

The staff gets together on a varying schedule at the co-working space and the rest of the time communicates electronically or by smartphone. Third parties manufacture and distribute the 25 flavors sold.

Andres Terech, a marketing professor at UCLA’s Anderson School of Management, said Halo Top may face a challenge maintaining growth without resorting to common business norms.

It hasn’t been a problem yet.

“Other businesses are going to realize this and start sharing co-working spaces where you only come in maybe three days a week,” Woolverton said.