By now, you expect the lines for the lamb tacos. Because after its early local cult following as a food cart spun into a series of restaurants that gained well-earned renown from the national media, the James Beard Foundation, and a showcase on Netflix’s Chef’s Table, pretty much everyone now knows that South Philly Barbacoa is one of America’s ultimate destinations for barbacoa.

“The best,” said TV host Andrew Zimmern, who happened to be at the taqueria on South Ninth Street last week interviewing chef Cristina Martinez when I visited. “She makes the fluffiest tortillas on the planet."

Zimmern was referring to the velvety, pliant rounds Martinez pressed to order before roasting them on the plancha. They’re made fresh with Pennsylvania corn grown from heritage Mexican strains that the restaurant nixtamalizes overnight and grinds into a masa dough. They’re amazingly vivid, in a way that seems to amplify the power of the Capulhuac-style slow-cooked lamb that Martinez and her husband, Benjamin Miller, sell by the steamy kilo to weekend crowds that begin showing up at 5 a.m.

But now there’s another reason to visit. The taqueria’s limited menu has been expanded to include quesadillas, which benefit from the same extraordinary masa, but are especially notable because they showcase fleeting seasonal ingredients — such as squash blossoms or fresh huitlacoche — with the rare bonus of Oaxaca cheese the restaurant makes itself. Ricardo Molanco, an employee at nearby Di Bruno Bros., comes once a week to hand-stretch the stringy white cheese, which is similar to mozzarella but more heavily salted and worked longer for a firmer texture. The freshness of the cheese, which I’ve not seen made anywhere else, adds a heightened sweetness and luxurious texture as it melts, accenting the quesadilla’s griddle-roasted textures and fillings.

If you’ve never tasted fresh huitlacoche, the fungus that grows on corn, swelling into black and powdery gray kernels (and is usually sold jarred), you’re in for a special treat. It has a firmer texture fresh, and once it gets shaved off the cob and sauteed with sweet white kernels, garlic, and epazote, it lends the quesadilla’s filling an inky-black, earthy depth that’s as magnetic as any truffle. Miller says that corn blighted with huitlacoche is currently in local abundance with their vendors due to the wet summer — but hurry, because the season may only last a couple more weeks.

Quesadillas with fresh Oaxaca cheese, $12 for three, 5 a.m. to 5 p.m. Saturday and Sunday, 9 a.m. to 4 p.m. Monday at South Philly Barbacoa, 1140 S. 9th St., 215-360-5282; on Facebook.