Reprising a successful first restaurant is a tall order. But that didn’t faze Nemanja Borjanovic and Melody Adams when they decided to add a new space to bijou Basque joint Donostia, which they opened in Marylebone in London in 2011. They had set a high benchmark: Donostia’s spare decor, small scale and faultless service (not to mention a menu that features delicacies such as crisp cod cheeks) caused a stir when it first opened.

The pair’s roomy new 70-cover premises are also in Seymour Place. Lurra – Basque for “land” – opened in late 2015 and is a fitting follow-up. The dinning room is a whitewashed, marble-topped affair with pale wooden furniture and pistachio-green upholstery selected by Adams. A shelf of design books at the back adds a homely touch, while the brass balustrade leading up the oak staircase, pointing to another 20 covers upstairs, is an elegant touch.

Like Donostia before it, the kitchen is overseen by Polish-born executive chef Damian Surowiec, who cut his teeth at Barrafina in Soho. The ingredients and dishes have retained their simplicity and honesty. The difference at Lurra (roll the “r”) is the hardware: there is a heavy-duty robata-style grill in the centre of the open-plan dining room. “It’s the heart of the kitchen and we cook over cedar charcoal,” says Surowiec. “Almost nobody has these in London,” he adds, nodding towards the fire-red peppers sizzling on the grill. “To find the right peppers you have to get them from Spain – from Galicia or Guernica.”

The peppers are just the tip of the iceberg when it comes to the produce that Surowiec carefully sourced before opening Lurra. During a year-and-a-half of painstaking research, the chef went to San Sebastian and elsewhere on numerous research trips and shook hands with the suppliers of items including cococha (hake tongues), chorizo, solomillo pork and jamón.

This is more than a job to Surowiec. Talk quickly turns to the colour, marbling and pH of his meats, and at what temperature you can expect the fat to melt. Not to mention the various merits of grilling a turbot whole. Sourcing and cooking are a real passion; this shines through in the detail and flavours of the grilled octopus with piquillo sauce and the 14-year-old Rubia Gallega prime rib.

“Opening a restaurant on the other side of town would have been obvious if we wanted to roll out a concept,” says Borjanovic. “We don’t want to be another chain,” adds Adams. Like Borjanovic, she worked in finance before a chance visit to San Sebastian ignited the idea of starting a restaurant. Opening a second space so close to the first was a happy accident. The couple fell in love with the new site as soon as they saw it. “Business-wise you don’t want to canabalise yourself but 80 per cent of our bookings are still by word of mouth,” says Adams.

Like Donostia before it, Lurra is a simple formula flawlessly executed: attentive owners and an obsessive chef are united in a mission to serve the best Basque produce they can find. It’s a recipe we’re glad they’ve stuck to.