The 35-year-old owner of In-N-Out Burger is now a billionaire

(CBS News)

All those Double-Doubles you have been scarfing down have been very, very good for Lynsi Snyder’s bank account.

Snyder, who had already inherited 50 percent of the company when she turned 30, had her 35th birthday this week. As CBS News reports, that milestone triggered the inheritance of most of the fast food joint’s remaining shares, valued at 1.3 billion dollars!

Snyder is now believed to be the youngest female billionaire in the United States and one of less than 300 in the world.

The heiress has been married four times and has suffered through numerous family tragedies – including the death of her father, who overdosed on prescription drugs when she was just 17 years old and a plane crash which claimed the life of her uncle.

In-N-Out Burger was started in 1948 by her grandparents, Harry and Esther Snyder, with a single hamburger standing in Baldwin Park. There are now more 300 In-N-Out Burger locations.