Every once in a while, restaurateurs in New York become infatuated with the cuisine of some other place.

In the 1980s, La Louisiana, K-Paul’s and Acme fed us jambalaya, blackened redfish and other tastes of New Orleans and Cajun Country. Three decades later, Aska, Luksus and Acme (the same space, without the chile-pepper lights and hot sauce bottles) introduced us to frizzled lichen and other totems from Copenhagen.

In the past six months, New York has found a fresh source of inspiration. The menus at two of the most popular restaurants this year — spots that have been extensively and breathily praised on social media, spots where hopeful customers patiently line up on the sidewalk through snow, rain and solar eclipse — are tributes to the cuisine of El Reno, Okla.

Fewer than 20,000 people live in El Reno, but the city has what may be the world’s highest concentration of establishments serving fried-onion burgers. The dish, made by mashing a great handful of sliced onions into a wad of ground beef and then griddling the whole mess until it is drippy and brown, was invented there as a cheap meal for workers who went without pay during the Great Railroad Strike of 1922. Today El Reno is to fried-onion burgers what Isfahan is to carpets and Paris is to baguettes.

For a long time, word about fried-onion burgers did not travel much beyond Oklahoma City. Today, though, if you mention El Reno-style burgers to the kind of New Yorker who knows where the latest pop-up is and what time you need to arrive, you’re likely to get a knowing nod. The person may mention the Oklahoma burger served just off Tompkins Square Park, or the kosher version made in Forest Hills, Queens. Sooner or later, though, the conversation will come around to Gotham Burger Social Club and Hamburger America.