It started with a call from the Associated Press and a question: What's a good recipe for a vegetable side dish that features common pantry products?In 1955, the AP, like other newspapers and magazines of the time, was running a feature of an easy-to-make Campbell's Soup side. The question came with a caveat: the recipe had to be built around green beans and Campbell's Cream of Mushroom Soup, two items most Americans regularly had in their homes in the '50s.The request fell to the Campbell's Soup Co. test kitchen in Camden, New Jersey, an arm of the company that focused on coming up with recipes for its products. Dorcas Reilly, a supervisor for Campbell's home economics department, was tasked with leading her team to figure out what could be done. The group would test and grade recipes repeatedly. Only a perfect score would qualify it as ready to go. In November of that year, Reilly and her team settled on what would be first known as "the Green Bean Bake," an easily adaptable six-ingredient recipe of green beans, cream of mushroom soup, milk, soy sauce, black pepper and French fried onions that takes 10 minutes to prep and 30 minutes to bake."We worked in the kitchen with things that were most likely to be in most homes," she told NPR in 2015. "It's so easy. And it's not an expensive thing to make, too."When Campbell's started to put Reilly's recipe on the cans of its cream of mushroom soup in 1960, the popularity of the dish hit new heights. More than 60 years since the dish was invented, green bean casserole is a Thanksgiving staple, with an estimated 20 million-plus American households expected to serve it this year, according to Campbell's.Throughout her life, Reilly, a culinary trail blazer during a time when women were often on the sidelines in corporate America, remained astonished at the success of a dish based on green beans and cream of mushroom soup, one referred to by Campbell's as "the mother of all comfort foods.""We all thought this is very nice, etc., and then when we got the feelings of the consumer, we were really kinda pleasantly shocked," she said in a Campbell's promotional video for the dish. "I'm very proud of this, and I was shocked when I realized how popular it had become."Reilly, an influential innovator of beloved comfort food in the U.S., died on Oct. 15 of Alzheimer's disease in Camden. She was 92. A visitation and celebration of her life will be held on Saturday in Haddonfield, New Jersey."We are deeply saddened by the passing of Dorcas Reilly, the creator of one of the most beloved American recipes, the Green Bean Casserole," Campbell's said in a statement, according to the Philadelphia Inquirer. "Dorcas was an incredible woman whose legacy will live on for years to come. She will be missed by her Campbell colleagues and all those who were impacted by her creativity and generous spirit."Campbell Soup Co tweeted "Today we remember Dorcas Reilly, storied Campbell employee & creator of the iconic Green Bean Casserole, who passed away earlier this week at age 92. Her incredible legacy will live on in more than 20 million American households this Thanksgiving."Born on July 22, 1926, Reilly was raised in Camden. She would become one of the first members of her family to attend college, earning her bachelor's degree in home economics from the Drexel Institute of Technology, now known as Drexel University, in 1947. She headed to Campbell's in 1949, where she was one of two full-time employees developing recipes for the company's home economics department.With the economy flourishing in the '50s, there was an appetite for meals that were easy to make, delicious and cheap. Reilly found success with a tuna noodle casserole, a tomato soup cake and a Sloppy Joe made from tomato soup."It was about the team working together," Reilly said in her college alumni biography. "I didn't do it; we did it."But things were different when it came to her most notable side dish. Campbell's has estimated that 40 percent of its cream of mushroom soup sold in the U.S. goes toward making Reilly's green bean casserole. And millions of Americans have adopted it as part of their Thanksgiving celebrations."Thanksgiving is the Super Bowl for green bean casserole," Jane Freiman, director of Campbell's Consumer Test Kitchen, told NBC's "Today" in 2015.Reilly's cuisine hit new heights in 2002, when Campbell's donated the original recipe card written by Reilly to the National Inventors Hall of Fame. The yellow recipe card resides in the same place as Thomas Edison's lightbulb and phonograph and Enrico Fermi's first controlled nuclear reactor.Her son, Thomas B. Reilly, told the Philadelphia Inquirer that his mom was humble about her career and never spoke about the achievement when he was growing up. It only started to come up more when she was recognized as the inventor of the dish."I think she was surprised," her son said to the Inquirer. "I think she was even more surprised at how much of a big deal it became. She was not a flashy person. She didn't bask in the limelight. She just went in and did her job every day, like most blue-collar people."Though she was known for her work, Reilly had said how "food should be fun and food should be happy." It was a mantra she carried with her in bringing green bean casserole to the Thanksgiving table. And millions would follow."I loved to go to work every day," she said at Drexel in 2009. "It was just another day's work." She added: "I hope you enjoy green bean casserole forever."