A popular taco truck specializing in Mexico City-style al pastor tacos, started by one of the co-founders of Papalote, has landed a new pop-up location near Union Square, in a former Chipotle.

Al Pastor Papi, the popular pink taco truck/trailer that launched in 2018 and made frequent appearances at Spark Social and elsewhere in San Francisco, is opening its first brick-and-mortar storefront just off Powell Street in Union Square. The newsletter California Eating first broke the news, and the Chronicle follows up with chef-owner Miguel Escobedo about the move.

"I’m combining everything I’ve learned into this new location," Escobedo tells the paper.

The new location for Al Pastor Papi at 232 O'Farrell Street, opening in June, is a former Chipotle (next door to Barlett Hall) — not to be confused with the still-open Chipotle a few blocks away at Sutter and Kearny streets.

The move is happening with the help of the Vacant to Vibrant program, which began in 2023 under Mayor London Breed and is ongoing, facilitating the revival of downtown by providing lease subsidies and/or free rent opportunities to small local vendors to occupy vacant storefronts.

Al Pastor Papi's food truck ceased operating in early January, with Escobedo hinting that it might return in "another form," but the truck did make a recent appearance at the Golden Gate Park bandhell.

"Union Square has always been a vibrant part of San Francisco, and I'm honored to bring Al Pastor Papi to this iconic neighborhood," Escobedo said in an official statement. "After taking time to focus on my health and family, I'm excited to share our beloved al pastor menu with the community once again. This pop-up represents a new chapter for us, and I can't wait to welcome both longtime fans and new customers to our O'Farrell Street location."

Not all of the Vacant to Vibrant storefronts have endured, and the program is meant to be time-limited. But at least three recipients of Vacant to Vibrant assistance, Koolfi Creamery, Hungry Crumbs, and Paper Son Coffee, have recently signed long-term leases downtown. Also part of the latest round of Vacant to Vibrant pop-ups are clothing company Nooworks and craft workshop company Craftivity.

Escobedo tells the Chronicle that the menu at the Union Square Al Pastor Papi won't be limited to tacos, and will include salads, tortas, burritos, and burrito bowls. There will also be vegetarian options for all of the above, including jackfruit and Impossible meat substitutes.

The core of the menu will still be pork al pastor, marinated and roasted on a trompo or vertical spit, as seen all over Mexico City but more infrequently in the Bay Area. The Mexico City tradition came about via cross-pollination of meat-roasting ideas from the immigrant Lebanese community there in the mid-20th Century — the trompo is basically a shawarma spit — with several taquerias in Mexico City claiming to be the first to serve al pastor.