The Lockhart, restaurant review: Brad McDonald has picked up the south-western ball and kicked it out of the park

At the risk of straying into territory staked out by my more lurid male counterparts, I once saw a strip bar in Nashville with a neon sign outside advertising '99 Beautiful Girls! And One Ugly One'. They can get away with that kind of playful hucksterism down in the American South. Here, outraged punters would be demanding refunds and invoking the Trade Descriptions Act.

Some of that good old-fashioned marketing cunning has been applied to reboot a business started in London last summer by two expat Texan couples. The Lockhart launched on one of Marylebone's more appealing hidden streets as a rather good local restaurant, specialising in the cooking of the American south-west.

Unfortunately for The Lockhart and its British chef, the opening was overshadowed by a wave of more exciting openings further east – the noise was all about dude food in Dalston, not mac'n'cheese in Marble Arch. So the owners decided to bring in a gen-u-ine American to take over the kitchen, in the form of Brad McDonald, who sounds like a quarterback, but looks like an alt-folk singer, complete with frontiersman beard.

With a background in a very different style of cooking – he worked at Noma and Per Se before building a reputation at Brooklyn's hip Colonie and Gran Electrica – McDonald has picked up the south-western ball and kicked it out of the park. His menu for The Lockhart 2.0 reworks the comfort food of the Deep South, and sounds thrilling even in a crowded market. Mallard gumbo over Carolina gold rice; Tokyo turnips and country ham; muffuletta, the classic New Orleans sandwich. He's even offering shrimp and grits – the grits presumably deployed in the same role as the ugly girl at the strip joint.

Returning to the airy, double-fronted dining room, I recognised at least one of the previous team, manager Bunmi. He's been joined upfront by the angelic Molly, wife of Brad McDonald. You could perm any two of the staff and come up with a convincing Kooples ad. The room, too, is just trendy enough, with its beaten-tin ceiling and mismatched vintage china. But with sturdy, well-spaced tables and low-level music, it's distinctly middle-age-friendly.

The lunchtime menu offers just five 'entrees' and as many sides, supplemented with a couple of specials. This is the comfort food of the Deep South reworked by someone whose influences lie in the Cool North, and its obsession with pickling and brining, heritage ingredients and foraging.

Take the catfish gumbo; somewhere between a soup and a risotto, and based on a complex meat stock as umami-rich as any ramen broth, it layered slippery rice, spiced pork sausage and okra under a scattering of spring onions, and tasted fresh, vivid and utterly alien. At that point I reset my dials to expect bold, regional cooking rather than southern stodge, and started to have fun.

Having eaten grits before (once) I thought I knew what I was in for: gruel, basically. Here, the ground corn is transformed, with a lot of butter and cheese, into a rich and silky polenta-ish thing of delight, and partnered with a fistful of sautéed tiger prawns, punchy with lemon juice. Again, with its Asian mushrooms, the dish seemed almost Japanese, though the unannounced addition of fried bacon was authentically American enough.

In fact, meat pops up in all sorts of unexpected places. Powdered bacon is scattered over an otherwise bland wedge salad of ranch-dressed iceberg lettuce and chopped eggs. Collard greens are cooked in ham stock and finished with smoked ham hock. And a side of dirty rice is blousy with chopped chicken heart and liver, though we were warned about that.

Star of the show was the Southern-fried chicken, as good as any in town: two fist-sized legs, the coating dark and crisp, the brined, buttermilk-marinated meat stupendously flavourful.

The heritage-with-a-twist theme continues with desserts. 'Ice box pie', apparently borrowed from McDonald's mom, is the long-lost Southern cousin of lemon meringue pie. And 'calas', beignet-like bites with a suave chocolate ganache dip, confirmed that deep-fried dishes really are the way to go when down south.

Next to us, two landlords discussed defaulting tenants while applying themselves with gusto to skillets of cornbread and fried chicken. Neither the menu structure nor the room lend themselves to a long, lingering lunch, but there's a bodega-like bar downstairs which demands a night-time visit. With all the dining action happening way out east, The Lockhart offers a great compromise for oldies and Dalston refuseniks, who crave gastronomic adventure and Brooklyn-style grunginess, but don't want to go anywhere remotely grungy to find it.

Food ****
Ambience ****
Service *****

The Lockhart, 24 Seymour Place, Marylebone, London W1 (020-3011 5400). For three courses including wine and service, around £25 a head (lunch), £50 (dinner)