Super troupers: Rhubarb catering staff take to the floor at Mamma Mia! The Party

Mamma Mia! The Party is set in the family-run Nikos Taverna on the Greek island of Skopelos, and the set-up comes complete with a fountain, olive trees and pink bougainvillea as far as the eye can see. Guests are served traditional Hellenic fare while actors sing, dance and perform around them, incorporating both diners and servers in the telling of the story.

The theatrical production, created under the gaze of executive producer and Abba star Björn Ulvaeus, is as slick as the West End show, with a script adapted for the UK by QI and Great British Bake Off host Sandi Toksvig. The storyline jumps from one hit to the next while following the lives of the taverna owners and their employees.

The cast itself numbers 14, bolstered by the 79-strong Rhubarb front of house team, whose costumes match those of the performers. Accordingly, as well as serving and clearing tables, the team must also be in character as Nikos' employees,working on the sun-kissed ‘island', which is kept at a balmy 22ºC despite its Thames-side location.

Rhubarb's general manager for the site, Jan Kraemer, who leads the team with Rhubarb director Chris Rettie, explains that the caterer, which holds contracts for the Royal Albert Hall and Sky Garden in 20 Fenchurch Street, among others, was passionate about winning the project to bring the attraction to London from its Stockholm debut. It is, they explain, a different proposition to anything they have experienced before, with team members being taught not just to present a dish but to do so on cue and in character – with a few dance moves thrown in.

Kraemer explains: "It was a completely different approach for both me and Oliver Wickham [executive chef for Rhubarb at Mamma Mia! The Party]. It's not ‘this is how you serve a table and this is how you serve a wine', it's ‘one-two-three-four, one-two-three-four' and ‘when the actor says X, Y and Z you need to do this'. It's a show first and then we work into that – we have to be quite efficient."

From welcome drink to coffee and baklava via mezze, starters and main courses, the service is carefully choreographed to the second, taking cues from the cast and requiring the team to work to strict serving timelines. It's a slick operation that has involved both front and back of house, from the design of the kitchen to the routes servers take on to the floor.

"I sat down with the script on one side and the sequence of service on the other and worked out what can happen when," says the general manager. "We write the restaurant sequence of service for the main course around when Debbie, the chef in the show, says, ‘the lamb is ready'. Working back from there, we have 10 waiters in the kitchen with trays ready to go out. I've read the script I think 50 or 60 times, just going back to the sequence of service and trying to marry those two elements together."

It's not just the timings that Kraemer has had to carefully plan. For the experience to come together cohesively for guests, he considered what impact the story would have on a restaurant team and how it would react.

This immersion in the Greek taverna has extended across the operation, as head of marketing Becky Barton explains: "It's all about authenticity. It's about enhancing the Greek experience. It is our job is to bring an amazing dining experience."

This is a show first and foremost and our job is to make sure we enhance that and bring an amazing dining experience

The caterer spoke to Greek chefs when developing the dishes, which include charred octopus with ouzo and wild oregano dressing, and lamb kleftiko with confit garlic and saltsa. This attention to detail continues in the carefully researched and designed table settings, as well as the wording – and spelling mistakes – on the menu.

"We wanted to have the taverna looking as Greek as possible," explains Kraemer. "The next step is looking for Greek olive oils and wines to really get the taverna style. The team asked ‘how would Nikos design his taverna? Would he just go to the local supermarket to buy his carafes?' That's the level we go to and we reflect that in beautiful food and produce – it really is the best of everything."

Putting on a show

The team's work would fall short, both on the floor and behind the bar, without a front of house team able to convey the feeling of the taverna alongside the cast. As well as knowing when to cross to a point on the floor without taking out a fellow performer mid-song, they chat casually about life on the island and, a points, join in with the flamboyant, choreographed dancing numbers.

Kraemer acknowledges that he was initially unsure how the recruitment would go. "I think my first thought was, ‘Where are we going to find 80 staff that really love Abba and are happy to listen to it every single night?'

Surprisingly, that was not difficult at all. "We were quite blessed: we had people signing up and being really interested. It's getting harder across the industry to hire, but here we genuinely had people saying, ‘So I get to dance and to work with food and beverage, all in the same role?' We got a lot of people from a theatre background or those who have had interactive, immersive careers.

"With the interview process, normally you would go through a person's background and where they have worked, but with this it's, ‘By the way, how do you feel about dancing?'.

"There's huge excitement across the business; we always look for characters, but suddenly that is a priority. Charismatic individuals are going to do well and that's a criteria because the training is pretty rigorous."

Intensive training was undertaken to help individuals develop their Skopelos personas before opening night. "We had a full week of training, for eight hours a day, before we opened," says Kraemer.

"The first four days were purely about the show, the script, the dancing – the parts where we need to react to certain things – and the rest was about the service and the operational side of things.

"We had daily improvisation classes about different scenarios. Part of the first week's homework was going away to build up a persona of ‘I've been living on Skopelos for the past two-and-a-half years and I live a mile and a half away, so I have to get the ferry every morning'. That really works well; the actors are walking around and we're all speaking to each other in character.

"It's a fun element: they drop everything outside and inside they are living in Greece. It's living and breathing the Skopelos way, adopting the story and being able to deliver lines so they feel comfortable."

Reviews of the first weeks of Mamma Mia! The Party fully endorse the efforts of the Rhubarb team, with many referencing being transported to Greece, as well as singling out the quality of the food offering and the team's front of house. For Rhubarb, the night is still young, with the attraction looking to run for years to come. As Kraemer says: "It's only going to get better."

About Rhubarb

Rhubarb was founded in 1996 as a premium events caterer. In 2008 it expanded to encompass standalone restaurants and full-time contracts at iconic London sites. The company has continued to expand and now has offices in London and New York, with a portfolio including Sky Garden and Coda by Éric Chavot and Verdi Italian Kitchen, both at the Royal Albert Hall. It is an accredited caterer at more than 70 venues across the capital and the Home Counties, as well as managing more than 1,000 events a year.

In 2012 ECI acquired a minority stake in the business, which would be taken on by private equity firm Livingbridge in 2016. The company is led by chairman Richard Prosser and chief executive PB Jacobse

On the menu

Mezze

• Selection of olives; vine cherry tomatoes with mint and balsamic dressing; homebaked bread basket; roasted red pepper hummus, taramasalata, tzatziki

Starters

• Traditional Greek salad

• Charred octopus with ouzo and wild oregano dressing

• Spanakopita

Mains

• Lamb kleftiko and confit garlic with saltsa

• Beef flank with Mediterranean sauce and chargrilled vegetables

• Sides: courgette briam, potatoes yiachni and cracked wheat with pomegranate and herbs

Dessert

• Portokalopita orange cake with confit orange and yogurt

Ticket prices from £135 per head to include a welcome drink, four-course meal, show and Abba disco