“We call it San Fran Barry,” laughs Sam Evans, co-founder of Hang Fire Southern Kitchen, about her and her partner Shauna Guinn’s choice to open a barbecue restaurant in Barry, nine miles south of Cardiff. “Yes, it’s tongue-in-cheek,” she adds, “but there is a touch of faded Americana about the place.” For the Hang Fire duo, bringing barbecue, or “south Welsh soul food” as they call it, to this often overlooked part of the world felt like the natural fit. Their menu takes us on a riotous road trip from New Orleans to Kansas City with a side serving of Texas and Tennessee, using Welsh produce to root it firmly in the Vale of Glamorgan. “This is homely cooking. It’s food for the people,” says Evans. “We couldn’t put Hang Fire anywhere else; we wanted to show Barry some love. Here, it just fits.”

Nevertheless, for the women, winning the OFM Best Restaurant Award after a mere two years in their first bricks-and-mortar home was a colossal surprise. “We were on holiday in Italy, our first break for six years, when we got the call to say we’d won. We were both in shock. I said: ‘This is very nice, thank you, but could you please do a recount?’”

Evans and Guinn met 19 years ago in Cardiff and quickly moved to London. “We were career girls,” says Evans. She worked in art direction, on magazines and in house for large corporate firms, while Guinn had a high-level role in social services. They earned good money but were unfulfilled. “There’s only so much of your soul you can give away.”

The pair puzzled over what they could do to merge their skill sets. Guinn is a force of nature with a natural front-of-house presence. She’s a bluegrass and country music enthusiast, and a singer and harmonica player whose party trick is to croon a slow mournful Appalachian version of songs such as Dancing Queen. Evans is a keen cook, a banjo player and a fellow bluegrass enthusiast. In 2011, the pair toyed with opening a bar or cafe, but it was a visit to Tom Adams’s much-celebrated London barbecue spot Pitt Cue that inspired them to head for the Deep South. “Pitt Cue was not like any barbecue Britain had seen,” Evans says. “We loved the sausage and the brisket but also the incredible slaw. We wanted to experiment with it and take it back to Wales. It was a tiny speck of an idea … and it just grew.”

In 2012, the pair headed to the States to soak up some cooking tips, with a plan to busk their way through the Deep South. They also had a yearning to meet a person dear to both of their hearts, the queen of country, Dolly Parton. They didn’t manage it, but they did meet her drummer, Steve Turner, and ended up sleeping on his floor. Hang Fire later went on to have their food requested by Parton when she played Cardiff, with the singer calling the brisket “the best she’s tasted in Britain”.

The pair’s six months in America turned out to be vital in a myriad of ways; it was a road trip, a musical pilgrimage and a fact-finding mission all at once. “We loved that every neighbourhood had a barbecue joint where the whole family would go,” says Evans. The pair ate their way through the southern states, picking up tips about cherry wood, custom-built smokers and how to make “yard bird” delicious. Southern-style barbecue is a complex affair, the devil is in the arduous detail and the pair watched chefs avidly. These tips are there in Hang Fire’s secret spice rubs and the porky roux in a gumbo. It’s in their sumptuous, pretty, red smoke ring around a brisket’s surface. It’s in ribs that glisten with a cinnamon finish.

When they flew home, they embarked on the first Hang Fire pop-up in a backstreet pub in Splott, Cardiff. News spread fast, and they were named Best Street Food at the 2015 BBC Radio 4 Food and Farming Awards. By 2016 they had set up permanent home in the capacious, sensitively restored Pumphouse close to Barry Docks. The building once generated the power for the world’s biggest coal port. Seeing it for the first time, the pair remember feeling “love at first sight”. Yes, perhaps the days when Barry is a mainplayer in global industry have gone, but Hang Fire want to be part of a new era of promise. “My hope is that more businesses, cafes and galleries open here after us,” says Evans. “It would be sad if this was a place where people just lived and commuted to Cardiff. Barry is wonderful, with a lot to offer.”

And Barry clearly loves Hang Fire. On a chilly Sunday in October just on noon, I attempt to nab a table for two without reservation, and am told in the most charming way that they could squeeze me in for an hour. Hang Fire wanted to feed me, oh, how they did, but for Sunday lunch their books were overflowing with Barry regulars in need of Texas toast and St Louis ribs. Hang Fire’s honest, generous, southern-style hospitality has caught the local imagination. Service is gorgeously enthusiastic and rather wonderfully there is no wifi. Customers who ask for the passcode are politely informed, “Conversation is free.”

We begin with a plate of hot, crunchy, exceedingly moreish fried okra served with a creamy Louisiana remoulade. Then, a plate of smoked Korean wings with toasted sesame seeds, spring onion and candied chilli. This is a menu that makes decisions difficult; there is Nashville chicken and waffles with whipped butter and maple syrup. There’s frickles (Creole-battered dill pickles), gumbo that’s teeming with smoked sausage, and bowls of shrimp ’n’ grits. We agonise over the sides, including a pastrami potato hash festooned with crisp onions, a mac ’n’ cheese and fragrant cornbread muffins. A tray of succulent, three-hour smoked yard bird appears with a creamy Alabama sauce and hot, fresh fries. My guest demolishes a tray of brisket with a pot of jammy, irresistible burnt ends. We finish with a warm, yielding chocolate fudge brownie with a scoop of salted caramel ice-cream.

I know I adore a restaurant when I’m already making plans for my return during the appetisers. That said, perhaps after the success of BBC Wales’s Sam and Shauna’s Big Cook Out the pair may no longer have time for the hospitality game? During the first series – a second has been recorded – they barbecued a whole pig with Barry Town United FC and filled the bellies of the Brecon Mountain Rescue team. Has showbiz changed anything? “I may be on TV now,” says Evans, laughing, “but I still very much feel like I work 80 hours a week in a basement while Shauna runs around upstairs.” At least this means the pair don’t get sick of the sight of each other? “Never,” she says, completely believably. “It’s been 19 years. Here’s to another 19.”