The former employee, Aisha Putnam, was the director of research and development for four years at the iconic Chicago chain. She was one of three people who had access to their private files.
The company said the recipes were guarded so closely, a thumb print verification is required to access them.
Putnam signed a non-compete as well as a confidentiality agreement.
After Putnam left the company, she signed a document saying that she deleted all of the information in her possession, but refused forensic review of her electronic devices.
The information she sent herself included product processes distribution agreements, supplier information, and pricing.
The lawsuit alleges that she took with her a USB containing 5,400 files containing the vast amount of information.