"What I like about ice cream is that it's not just a food," says Amy Simmons, the founder of Austin-based Amy's Ice Creams. "People don't just go to an ice cream store because they're hungry. They go because they're happy or because they want to celebrate or because they're going on a date. It can be a reward. There's something about it that's just bigger than a food."

"Ice cream," she says, "is magic."

It's also, practically speaking, a very good business—for Simmons, at least. In 2010, the company brought in $6.2 million in revenue throughout its 15 Texas locations. It employs about 200 people, many of whom are part-time high school students.

Simmons, a Michigan native who attended college at Tufts University, started the business in 1984 after studying psychology, biology, and taking the pre-med track as an undergrad. On nights and weekends, Simmons worked in Steve's Ice Cream, where, she says, "I always left feeling happy."

At 23, Simmons decided to put her career in medicine on hold. She filled out a business plan template she'd received from the Small Business Administration, scraped together a $100,000 loan from colleagues in the ice cream business and headed south for Austin to open up what would eventually become the eponymous ice cream shop she's run for the last three decades. (The choice to open in Austin was not completely random—Simmons had read an article in The Economist that the tech industry was booming there. And unlike her first choice, London, the weather was just right for a year-round ice cream shop.)

Amy's Ice Creams sells a wide variety of flavors and concepts, including "Amaretto Peach" and "Peanut Butter Honey." According to Simmons, the company exclusively uses "the highest-quality-super-premium-ice-cream that we could make:" A core principle of the company.

And despite the company's commercial success over the last 27 years, Simmons notes the difficulties in achieving profitability. "It's a tough financial business to sell $4 ice cream and make the kind of rents you pay," she says.

Amy's Ice Creams doesn't advertise. Instead, the company relies on community outreach and charity work to communicate the brand's message. Each store creates its own customer events; recently, one store hosted a Hawaiian night where customers who got dressed up received a discount. Another store had customers dress up as characters from Thor.

"Our mission is to make people's day," says Simmons. "That's what we're selling—a break from a stressful world."