The beef slides off the sharp knife like silk off silk.

The cooks, father and son, add no rub or marinade to the outside skirt cut. Instead, they gently drape the fillets over a small, very hot outdoor grill fueled by coals and thick staves of wood. They flip the meat constantly for six to eight minutes. Then they combine the meat and juices in a heated slow cooker before fanning out the cuts on a wide cutting board.

In seconds, they are rendered into “little sashes,” or “fajitas.”

Driven by the urgent, smoky scents, the hungry guest forks a juicy fajita onto a standard-size flour tortilla and then tops those earthy elements with a dash of salt and a generous sprinkling of homemade hot sauce.

Heaven.

At least as served in a modest Travis Heights East ranch home by the “Fajita King,” Juan Antonio “Sonny” Falcón, 81, who is credited with introducing the fajita to the general public in 1969 at a Diez y Seis celebration in Kyle, and his proud son, John Falcón.

Fifty years ago, the elder Falcón worked as a butcher in Guajardo Cash Grocery & Market, a popular store run by his formidable mother-in-law, Soledad Guardiola Guajardo, at Ninth and Lydia streets in East Austin. Guajardo, who died in 1983 at age 77, also founded KMXX, Austin’s first Mexican American radio station.

Sonny switches on memories of his lightbulb moment.

“I had been at the house, experimenting with skirt steaks, which were usually trimmed off and run through a grinder to make hamburger,” Sonny says. “So I made a little mock fillet with a piece of skirt. I put a piece of tallow in the center, rolled it up and then wrapped it with bacon and put it in the broiler. It turned out to be the tastiest.”

Sonny knew he was onto something.

“No spices, no tenderizer,” says Sonny. “Just tasty and tender. I told people in the store, ‘Man, here's a cut you can take home and cook and it's going to be real good.’ I grilled part of it, chopped it up, put it on a flour tortilla, put on some hot sauce, and man, I thought, this is going to replace the hot dog.”

The case for being first

Some food historians suggest that the fajita — basically, grilled meat on a tortilla, a Tex-Mex dish, not interior Mexican — grew out of vaquero food customs in the Southwest during the early part of the 20th century.

“You might want to argue whether the vaqueros of South Texas were eating skirt-steak fajitas or, actually, tacos al carbon, which can be any cut of beef,” says John Falcón, the keeper of his father’s culinary flame. “But I assure you they weren’t riding around on horseback with pre-made tortillas in their saddlebags. Or that they carried around someone to make tortillas.”

In any case, the word “fajita” did not enter general usage until the early 1970s, according to the Oxford English Dictionary. It first appears in the American-Statesman in meat market ads in 1974. The first editorial article citing “fajitas” — in quotation marks, indicating a newish word — was published on Aug. 11, 1976, when Sonny’s creations were featured on Italian Night during Aquafest, the city’s former music and aquatic entertainment festival.

“We offer … a variety of ethnic culture, letting everyone do their own thing,” Charles Villaseñor from the festival said about Italian Night in that 1976 story. “There’s music and noise going on all the time.”

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John’s careful searches have not uncovered a single menu, grocery store or butcher shop selling something called fajitas before his father’s commercial booth at the Diez y Seis de Septiembre celebrations in Kyle, which probably fell on the weekend prior, so maybe Sept. 13, 1969.

“There are no journal entries, etc., recording such meals,” John says. “The only entity that is remotely close — as far as timeline — is the Roundup Restaurant in Pharr. And when you look into their history, they were placing the cut on nachos.”

Many Texans remember sizzling fajitas — the sizzle came from lime juice squeezed over hot cast-iron plates, not the beef — at the famed Ninfa’s restaurants in Houston and elsewhere.

“Mama Ninfa didn’t even open until ’73 in Houston,” John says. “And she started by selling ‘tacos a la Ninfa,’ a registered trademark of hers and a play off tacos al carbon. It wasn’t until the first major boom of awareness and popularity happens in the late ’70s that they drop ‘a la Ninfa’ and start calling them ‘fajitas.’”

Quite the family

In any case, the family’s history has been documented in tremendous detail. A long western wall in the Falcón home serves as an educational Fajita King exhibit. Numerous framed stories from multiple publications attest to Sonny’s exploits and popularity as well as to his friendship with country music stars and golf pros.

On the same wall is a prized ad for his frozen barbacoa de cabeza. Sonny was the first butcher to receive a state license to manufacture the product, which traditionally took Mexican families hours to cook.

Juan Antonio "Sonny" Falcón was born in 1938 in Mercedes in the Rio Grande Valley. His stepfather, Gregorio Vega, had come from Mexico.

“He was a wonderful man and a hard worker,” Sonny says. “He served in the Army in World War II and passed away in Austin.”

Sonny’s mother, Maria De La Luz Vega, was born in Mission.

“She took care of other people’s kids and did housework,” Sonny says. “Of her three children, I was the youngest. My older brother, a gung-ho Marine, never came back from California. My sister, the middle one, still lives in McAllen.”

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A star baseball and basketball player, Sonny never got into serious trouble, but his innate sense of fair play irritated people in authority.

“I got blamed for stuff,” he says. “I lived a clean life. Never went to jail for anything. But I would argue with people about social issues. They called me a troublemaker.”

He remembers on a road trip back from California seeing a sign in Pecos that read, “No blacks, no dogs, no Mexicans.”

Sonny nevertheless finished high school and attended Pan-American University, now the University of Texas Rio Grande Valley. He rose early each morning to hitchhike to Edinburg.

“I didn’t have a nickel to my name,” he says. “I thought, ‘This ain’t for me.' I had to go to work.”

Sonny moved to Austin in December 1958. His first job was at Glastron Boats, one of the city’s key manufacturers at the time. Glastron garnered brief fame in 1966 for providing the stunt boat in “Batman: The Movie,” and the movie made its world premiere in Austin.

“They employed a lot of people from the eastside,” he says. “The fiberglass gets into your system. Seems like you can’t get rid of it. We were all issued just a little mask. I wore two shirts and two sets of trousers to keep it off. I was sanding fiberglass in an unventilated room that was as hot as hell.”

That didn’t last long. He interviewed with the Knippa family, which owned the Austin Meat Company.

“Neat people,” Sonny says. “They treated everybody good. I worked in a room packing ordered cuts for five or six years.”

While working at Austin Meat Company, he married Guadalupe Guajardo, an Austin native whose widowed mother, Soledad Guajardo, was a savvy businesswoman who invested judiciously in real estate, mostly in traditionally African American neighborhoods.

“She was a real proud Mexican,” Sonny says of his mother-in-law, whom some in the community referred to as the “Godmother.” “That came back to haunt her later on. When she started her radio station and applied to the FCC for a license, the government said that because she was not a citizen, she could not own more than 10% of the business.”

Soledad Guajardo wore a severe black skirt and white blouse every day and was not shy about exercising soft or hard power.

“They talked about Roy Velasquez of Roy’s Taxi being the No. 1 ‘patron’ in East Austin,” John says. “She was No. 2.”

Sonny and Guadalupe had three children: John, 56, Robert, 51 and Jose, or “Joe,” 49. At first the family lived at 801 Lydia St., not far from the family grocery store.

John: “My little footprints are still in the concrete between the front door and the driveway.”

The other boys — both went into the funerary business — were born while they lived on Woodland Avenue, where the extended family moved into nearby houses in 1964. Soledad Guajardo also tended a little ranch not far away near Parker Lane and Oltorf Street.

‘Something I want to do’

Soledad was not the only entrepreneur in the family. Once Sonny had conceived what he called a fajita, he wanted to spread the word — and make some money.

“When I thought I had perfected this taco, I went to my mother-in-law,” Sonny says. “I told her what I wanted to do. She says, ‘You don't need to do it. Your family is taken care of.’ I said, ‘It's not a need. It's something I want to do.’”

At the time, Kyle threw one of the biggest Diez y Seis fiestas in Central Texas.

“I wound up there for a couple of days,” Sonny says. “I sold $13 worth. Somebody else probably would have given up on the idea. I kept looking for other places to go.”

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Happily, Sonny connected with Jimmy Mosley, who co-founded G&M Catering and G&M Steakhouse.

“He had all these contracts for food spaces during concerts and festivals,” Sonny says. “He was a helluva guy. He knew his percentages. One day, I approached him, and I wound up at Aquafest. And the fajita started to catch on.”

It helped that Wally Pryor of the Pryor entertainment clan promoted Sonny’s food booth over the PA system.

“‘You need to go over and try this,’ Wally would say,” Sonny recalls. “But people grumbled, ‘Look at the sign: “fajita.” It doesn't even sound good.' They didn't see that a ‘faja’ is long sash, and that ‘fajita’ was like a little belt. But I brought my grill right up to the point of sale.”

That sensory strategy worked.

“He was like a golfer; everything was free-standing,” John says and laughs. “He’d pick up a blade of grass to see which way wind blew, then he moved his grill so the wind could do its thing with the smoke.”

Eventually, the Fajita King became something of a beloved character, quickly identified by his old-style cowboy hat, flowing hair and full beard.

Sonny stepped away from the grocery store because of a family rift in the early 1980s.

He continued to man the Fajita King food stands — and was written up in Playboy magazine in 1987 — and cooked scores of beef heads a day for his frozen barbacoa de cabeza.

In the 1990s, he helped out at his son Robert’s mortuary service by prepping bodies, transporting ice and driving the hearse.

“I carried bodies all over the place,” he says.

His wife, Guadalupe, died last year.

Over the years, Falcón family members have become experts of a kind on culinary history.

For instance, John likes to point out that cutting-edge Mexican or Tex-Mex eateries first put fajitas on their menus in the late 1970s.

“If you were long established, say, like Matt’s El Rancho, you may have waited until the early ’80s,” John says. “And then there were the old-timers like El Patio who never put them on their menu.”

To some eaters, fajitas seem to have been with us always.

“I believe that if you are younger than 55, you probably don’t know any better,” John says. “You believe that fajitas have been around since Jesus Christ, that you would have found them on menus forever right next to the tacos and enchiladas. Older folks need to be prodded to remember — what a rush of excitement there was around this new dish.”