One day, no one in Dallas-Fort Worth had ever heard of birria tacos. The next day, everyone in town is doing them.

Crispy, cheesy, and meaty, this special taco twist has become the flavor of the moment at a host of eateries across DFW, from Chalio's in FW to 225 BBQ in Arlington to Maskaras Mexican Grill in Dallas' Oak Cliff.

More than a dozen restaurants, food trucks, and taco stands have added birria tacos, also called birria de res, served with a consomme broth on the side for dipping.

Two new Fort Worth eateries — Calisience and Birrieria y Taqueria Cortez — have seen mobs of customers lining up, seemingly all for their birria tacos.

Birria is a stewed meat dish with roots in Jalisco, a state on the west coast of Mexico, where it's often served at celebrations such as weddings and holidays. The meat can be beef, goat, or lamb, says Jose Meza, executive chef at Jalisco Norte, the Mexican restaurant on Oak Lawn Avenue in Dallas. Meza is from Mexico City; his wife is a native of Jalisco.

"Most of the time, birria is made with lamb and a mix of dried chiles," he says. "It becomes this rich soup with shredded meat, which you can eat as soup, garnished with onion and cilantro, or with tortillas on the side, with the option of making your own tacos."

But placing the meat inside a taco, adding cheese, then cooking it on a flat-top grill until the whole turns crispy and oozy — that's another thing entirely.

Like so many buzzy things, the birria taco trend started in California. Eater tracks it to Los Angeles, but with roots in Tijuana, Mexico, the first place they started putting birria in a taco, adding melted cheese, and cooking it on a grill.

A key component of a proper birria taco is the consommé, says Rene Ramirez, who owns 225 BBQ, a catering and food truck operation in Arlington, with his wife Joyce.

"The consomme is a flavorful broth with spices," Ramirez says. "You dip the taco into the consomme, which gives it a reddish flavor, then slap it on the grill with oil and a good amount of cheese. It's a great crunchy, cheesy taco. From the first week we did it as a special, people have been demanding it, so we're making it a permanent menu item."

Rogelio Cortez, who owns Birrieria y Taqueria Cortez, helped usher in the trend when he started selling his "quesatacos" in February.

"We don't do them too crunchy," he says. "We use two tortillas, that's the way they do back where I come from in Guadalajara. We have our own style — not soggy in the middle but not too crunchy. If they get too crunchy, they start losing flavor."

Meza says that it's great when trends gather steam, but important not to lose sight of the value of the original dish.

"Dallas is very trendy, it's funny when everybody starts picking these things up, I remember the same thing happened with hoja santa, the Mexican herb, a few years ago," he says. "These things pop up, but birria is not something that's easy. It can be very tricky. There are secrets behind it to make sure the flavors remain authentic. It's easy to do a soup — but there's more to it than that, to develop the layers of flavors that a good birria should have."

In good news for trend watchers, there's a new dish from north Fort Worth taqueria Tres Betos waiting in the wings: birria ramen.

Here are some of the DFW restaurants selling birria tacos right now:

Birrieria Los Chivos de Oro - family restaurant in south Fort Worth.

Birrieria y Taqueria Cortez - truck in south Fort Worth.

Caliscience - Fort Worth food truck with California roots.

Chalio's Mexican Restaurant - serving lamb and goat stew, plus a birria tacos plate with two tacos plus rice and beans.

La Antojeria Jalisco. Stall inside Long Street Bazaar is from husband and wife Jalil and Yessica Saldana, natives of Jalisco.

Maskaras Mexican Grill - owners of this Oak Cliff spot are from Jalisco, birthplace of birria.

Paco's Mexican Cuisine - Restaurant on Magnolia has been doing them as special on Fridays and Saturdays.

Taqueria y Birrieria 3 Coronas - Mexican restaurant in southeast Fort Worth.

Tres Betos Taqueria - doing them crunchy on the north side of Fort Worth.

225 BBQ - Arlington food truck started doing them as a special and are now adding them to the permanent menu.