How do you do that? You open a new tapas bar, and just a couple of days in, you're an instant party. I guess it helps when you bring your own crowd along with you, which is something that team Porteno has always done.

The original Porteno was heaving from day one, as was Bodega and The Continental. Bastardo felt like an Italian festa, and Humble Bakery's queues rose from scratch as if driven by yeast.

Here at Bar Louise, where the 1950s pink and purple facade of the Marie-Louise hair salon still stands, albeit gently corrected to read Marie-Louise Salon de Tapas, it's happening again.

The couple in the line ahead of me are told it will be an hour's wait. I have a 7pm booking upstairs, which I immediately regret as I thread my way past the downstairs marble bar, packed with chatty snackers.

"You hungry?" I hear one diner at the counter ask his friend. "No, I just woke up."

Traditionally, upstairs dining rooms are like Mars, with no discernible atmosphere, but nope, it's another party, with tables wedged in everywhere, food all over the place, trays of house sangria sailing past, and A LOT OF NOISE.

The festive atmosphere is pushed further by the presence of Porteno team players. Mikey Nicolian​ checks reservations at the door, Rachel Doyle attends to tables, Joseph Valore glides around the dining room like a majordomo, two or three bottles in hand, and the dark terracotta walls and '50s detail speaks to the work of interior stylist Sarah Doyle.

In the downstairs kitchen, founding chefs Ben Milgate and Elvis Abrahanowicz reunite to cook as one, alongside head chef Marcelo Munoz, formerly of Continental Deli.

But what to have? The gilda ($6), a staple of the Continental bar menu since 2015, sees green olive, salted anchovy and guindillas pepper.

Slide it off into the mouth, and it's yet another party, teamed with a Partida Creus MUZ vermut ($12) served over ice. Fleshy mussels escabeche in a lemony prawn oil dressing ($16), same.

Jamon is a must, but which? You get quite a lot of freshly sliced serrano for $18, and crusty bread is available ($3 per person), but the smaller amount of paleta (shoulder) Iberico ($32) comes with potato crisps, which could be a deal-breaker.

You could just go into rotation on vermut and jamon, but the raciones or larger dishes are too interesting to ignore, with five vegetable-based, six seafood and eight meat.

Escalivada ($20) is a fruity pile of grilled-until-collapsed eggplant and different peppers, and the classic pulpo a la Gallega ($28), a Galician mix of grilled octopus and soft, waxy potatoes under a shower of smoky paprika, comes on a creamy aioli base.

There's a jazz improv vibe to the food tonight – it comes fast, it comes wrong, it doesn't come at all, or it comes twice. A sweet dark, meaty slab of house-made morcilla is the star of a fry-up involving green peas and a fried egg.

Sausages rule, with plump, house-made butifarra (a white pork sausage from Catalonia) shrouded in wilted escarole beaten up with chilli. The meat is smooth and gently, proudly porky, a natural match for a fresh, intense 2020 Comando G La Bruja de Rozas organic grenache.

Dessert is a thick slab of torrijas ($14), like pan-fried French toast crusted with sugar and smelling sweetly of cinnamon and orange zest. And that's it – it's over and you're out on the street, still reeling with flavours and smells and noise.

They could definitely pull back on the fast and furious serving pace and still get the turnover and the energy they need.

There's something appealing, though, about the unsophistication, the messy mayhem, the focus on drinking over eating and the holiday atmosphere, set against the hustle and bustle of staff. 

The food and drinks do what they always do when they're allowed, which is bring people together to have fun. Like I said, it's a party.

The low-down

Bar Louise

Vibe Instant tapas party, upstairs and down

Go-to dish Mussel escabeche $16

Drinks Estrella on tap, classic cocktails, dozens of vermuts and sherries, and wines divided by white, rose, orange and red.

Terry Durack is chief restaurant critic for The Sydney Morning Herald and senior reviewer for the Good Food Guide.