The key to survival in a changing ecosystem is not being the strongest organism, but the one that can adapt and modify its behaviour to the changing environment.

"We don't do suits any more," says Craig Hemmings, as he scoots around the new Wine Room at Manly Greenhouse in jeans and sneakers. "That person is gone. I had to exorcise him."

Luckily he hasn't thrown everything else out as well. The sort of skills honed over years as restaurant manager at Guillaume at Bennelong, Black By Ezard and Bistecca in Singapore aren't easily shed. It's muscle memory now, ingrained. (Same for me, but at the table.)

While downstairs at the Greenhouse is still a more casual Mediterranean eatery, and upstairs is a rooftop bar, Hemmings has relaunched the first-floor grill room as a relaxed wine bar, with a menu of small dishes inspired by the Basque region.

The handsome, ocean-facing room is broken up with leather-clad banquettes, shelves of wine and glass screens, and comfort levels are high. There's a subtle nod to Miro in the organic shapes of Melbourne artist Kayleigh Heydon's abstract mural on the wall, but most eyes are tuned to the view of Norfolk Island pines, squealing kids and white-fringed waves.

Chef James Evangelinos brings a thorough fluency in charcoal grills and wood-fired ovens from his time at Woollahra's Centennial. The result is an easy flow of small to large dishes, some Spanish, others Frenchish or Greekish. Wood-fired peppers, say, or chargrilled baby squid or jamon serrano – kissing cousins.

But first, let's talk potato crisps, that staple of your typical neighbourhood Basquaise pintxos bar. Even El Bulli's experimental chef Ferran Adria developed new flavours for Fritos Lay's back in the noughties. I'm a bit in love with these, though – house-made, crisp as hell, and showered with spritzy thyme, lemon zest and fennel seed salt ($6).

If you stack two crisps together for ballast and place a juicy, smoky, spring bay mussel (four for $8) on top, you've just created your own pintxo. Ha, who needs Adria? It's just made for a glass of Pazo do Mar Expresion Albarino ($12) from Spain's Pazo do Mar from the succinct by-the-glass selection.

Service is a strong point, with wine-savvy restaurant manager Maureen Er bringing Singapore smarts and grace to the table. When I order a platter of ruby-red, almond-scented jamon Iberico ($22) – hand-sliced, such a rarity in Australia – she's happy to bend the rules and swap the crusty wood-fired bread for the downstairs bistro's puffy wood-fired flatbread to go with it.

Time and again, Evangelinos brings disparate ingredients together in a warm wash of flavours. Pine mushrooms ($14) are cooked escabeche-style in spiced wine and served with serrano and a confit egg yolk that mingles to form a lively sauce.

When I ask how he gets a pile of grilled duck livers ($12) both scorchy and spreadably pink, his answer is simple. "Concentration." Add to that answer: caul fat, a good chargrill, a serious glazing with a superb Toro Albala pedro ximenez vinegar and duck jus, and some baby onions and crisped sage leaves. All that work for a $12 dish? Gee, this is a tough game.

The pork belly ($24/$35) is a dream, all sweet confit meat and crisp crackling, with a soft herb salad. Again, concentration. There are scotch fillets and sirloins as well, so as not to waste the award-winning 400-bottle wine list.

Mmm, Vin Santo baba, or madeleine cake with dulce de leche? Nope, it has to be Basque cheesecake ($12), the beautifully blackened, full-bodied, rich-but-light cheesecake invented by chef Santiago Rivera at San Sebastian's La Vina restaurant in the 1990s. It's soft and light, enriched by warm, lush, seedy figs to one side.

Manly is a famously tricky environment for any restaurant with ambitions above and beyond a burger and a beer. The Wine Room stands out among its neighbours, aiming higher – and delivering real value – while still wearing jeans and sneakers. Good luck to it.

Drinks: House cocktails, local beers and a serious 400-strong wine list with a growing proportion of Spaniards.

Vegetarian: Limited, but several dishes can be adapted.

Pro tip: Begin or end with a drink on the rooftop cocktail bar, Friday to Sunday.

Terry Durack is chief restaurant critic for The Sydney Morning Herald and senior reviewer for the Good Food Guide. This rating is based on the Good Food Guide scoring system.