The youngest female billionaire in the U.S. has made a fortune on fast food.

But the story of Lynsi Torres, the 30-year-old owner and president of the beloved In-N-Out Burger chain and one of the world’s youngest billionaires, largely remains a mystery, Bloomberg reported.

Torres, who has no college degree and little business training, inherited the West Coast-based company from her grandparents, Harry and Esther Snyder. Torres’s family has transformed the couple’s initial, tiny drive-thru shop into an estimated $1.1 billion empire.

The Christian-themed chain, founded in 1948, now includes almost 280 stores in five states and boasts a slew of big-name fans, including billionaire Warren Buffett. Hoards of loyal customers line up for hours before a new store’s opening to get a taste of the chain’s famed “animal style” patties.

“They have done a fantastic job of building and maintaining a kind of cult following,” Bob Goldin, executive vice president of  food industry research firm Technomic Inc. in Chicago, told Bloomberg. “Someone would love to buy them.”

Despite her success, Torres has kept notoriously mum on both her public and private life — and rarely gives interviews.

The hamburger heiress, who has been married three times, was named head of the company in 2010 following a series of deaths in the family.

Harry Snyder died in 1976. His second son, Rich, served as executive president until he passed away in a plane crash in 1993 at the early age of 41.

Torres’s father, Harry Guy Snyder, then took over and grew the chain to 140 restaurants before he died from a prescription drug overdose in 1999.

Torres’ grandmother, Esther Snyder, stayed in control of the company until she passed away at age 86 in 2006. Torres received half ownership of the company when she turned 30 and will receive the second half when she celebrates her 35th birthday.

“I have no clue about her,” Janet Lowder, a California restaurant consultant, told Bloomberg. “I was even surprised there was a granddaughter.”

In September 2012, Torres made a rare appearance in news headlines for buying a seven-bedroom, 16-bathroom mansion, worth $17.4 million, in the swanky California neighborhood of Bradbury, according to Realtor.com.

While she’s silent about most other things, Torres has been outspoken about her interest in drag racing. Her current husband is race car driver Val Torres Jr.

“My father had a passion for drag racing and that passion lives in me,” Lynsi Torres once told CompetitionPlus. “Drag racing has played a big role in In-N-Out’s history and it is also an important part of my family history.”

Torres, however, is not alone in her quest to stay out of the public eye. Goldin said most of In-N-Out’s upper management employees are the same.

“I’ve been in the industry a long time and I don’t think I’ve ever seen any of their people at an industry meeting,” he told Bloomberg. “They’re very quiet. That’s their culture.”

 

Compared its employees, the company itself has been relatively open about its religious views.

Discerning customers will notice that the company prints biblical verses on its soft drinks cups and food wrappers. Some of their milkshake cups, for example, cite “Proverbs 3:5,” which reads “Trust in the Lord with all your heart and lean not on your own understanding.”

In-N-Out has never made any explicit statement about the decision to add the religious notations, which Rich Snyder called for in 1987.

“He told me, ‘It’s just something I want to do,” company spokesperson Carl Van Fleet once told USA Today.