The iconic Philly cheesesteak—thin slices of beef piled onto an Italian bun and topped with grilled onions and Cheez Whiz (sorry Provolone proponents, it ain't a Philly cheesesteak to me without the neon Whiz)—was invented in 1930 when Pat and Harry Olivieri improvised with some leftovers to make a sandwich to sell at their South Philadelphia Italian market stand when they ran out of hot dogs.

The happy accident is one of my favorite guilty pleasures, a must-have whenever I'm anywhere near Philly. And it got me to thinking about what other potential accidental, yet crave-worthy combos were lurking in the culinary ether.

"What was an afterthought turned out to be one of my most popular dishes ever," says Chef John Bonnell of Bonnell's Fine Texas Cuisine in Fort Worth, about his signature fried quail leg dish, which he concocted after a supplier accidentally sent him a pack of 20 quail legs. He estimates that he's sold more than 20,000 legs over the past 10 years—and not only has the item helped increase sales, there's the intangible boost that comes from having a dish customers can't get anywhere else.

On a more casual note, Las Vegas Chef Anthony Meidenbauer was working at a casino resort where a frequent high roller was vegan. One day, the guest popped in unannounced and requested the chef make him a fresh veggie burger. So he quickly pulled together a patty made of avocado, sprouts, and cucumber and served it up. The vegan VIP loved it and the URTH burger is now served at Meidenbauer's current post at Holsteins Shakes & Buns at the Cosmopolitan Hotel.

Finally, there's a dish that I'm dying to try at Maialino in New York City. Originally conceived by Chef Nick Anderer to use up the unused legs from their suckling pig entree, as well as leftover pieces of pasta that remain after the pasta is cut, Malfatti al Maialino is a heavenly sounding ragù of ham, veal stock, butter, arugula, and lemon served over pasta. It's the restaurant's best-selling pasta dish according to the New York Times. "Cook what you might otherwise throw away, and if what you're cooking is delicious, the restaurant's profit margin increases," wrote Times restaurant critic Sam Sifton of the dish.

What do you think of happy accident signature dishes? Do you think it helps draw more customers, or is it just savvy marketing?