The nation’s oldest Mexican restaurant is approaching its 92nd year in business and shows no signs of slowing down. So what’s the secret ingredient to El Charro Cafe’s success?

In a word: Family.

Mónica Flin opened the doors of Tucson’s famous eatery in 1922, after a bad divorce left her in search of employment. At the time, it was unheard of for a woman to open her own business. Nine decades later, her small restaurant has grown into one of southern Arizona’s most successful businesses.

Her great-grandniece, restaurant owner Carlota Flores, now continues the family legacy of strong businesswomen.

“Tía Mónica didn’t let anything stop her. Whether it was a bad marriage, or cancer, or the Great Depression. She always found a way to make a plan and have a job,” Flores told Fox New Latino, regarding her great-grandaunt.

My hope for my family is that we can celebrate this restaurant’s 100th year in business. After that… we’ll re-evaluate the dream.

- Carlota Flores

In addition to creating a family legacy that spans over 90 years, Flin is also known for reportedly creating the famous ‘Chimichanga.’ According to family legend, she invented the dish after accidentally dropping a pastry into a deep fat fryer.

The family slowly grew Tia Monica’s vision into a culinary enterprise. El Charro Café now boasts five Tucson-area locations, a full service catering division, and is the Official Mexican Food Restaurant of the University of Arizona Wildcats.

“There’s nothing like a family business. You know you can call someone at anytime, and tell them you really need their help — without having to worry about payroll,” Flores said, about the importance of keeping it in the family.

The classic Mexican cuisine attracts diners from all over the country, including regular Sen. John McCain, a Republican who has represented Arizona in Washington for decades.

But the family’s success hasn’t made them blind to the high number of restaurant closings in the area. Five different historic Tucson restaurants have closed shop since April. The eateries had over 140 years of business between them.

“I’m 67 years old, and it’s definitely the hardest things that’s hit my industry in recent years — to see people that no longer have their business. Families who have been in business for years have no other option but to close the doors and leave,” said Flores.

As for the future of El Charro Café, Flores has one very special goal in mind.

“My hope for my family is that we can celebrate this restaurant’s 100th year in business. After that… we’ll re-evaluate the dream,” said Flores.

Aalia Shaheed is part of the Junior Reporter program at Fox News. Get more information on the program here and follow them on Twitter: @FNCJrReporters