If you haven’t eaten a katsu sando yet, there’s a good chance you soon will. Every year we tackle an onslaught of food trends; we’ve seen the rise and fall of courgetti and the weary acceptance of smashed avocado; we’ve recoiled in horror at the abomination that is the unicorn latte and we continue to enjoy the blissful carb-heavy highs of the pasta renaissance.

As for 2019, it undoubtedly belongs to the katsu sando – a Japanese take on the sandwich which sees breaded pork, tangy sauce and shredded cabbage tucked into two slices of fluffy brioche. Since they hit our shores Instagram has been awash with crispy cutlet cross-sections, and long may it continue; not only does the pleasing geometry and perfect meaty cuisson make the sando a bonafide social media star, it also does the business in the flavour department too. We’re no strangers to the joys of breaded, deep-fried meat and the UK is famously fond of a sandwich, but the katsu sando takes this combo to new levels entirely.

Flick through #katsusando on Instagram and you’ll see hundreds of imposter sandos. Some are worthy pretenders to the throne; others are just regular sandwiches masquerading as the sandwich du jour. If you’re after the original sando – the one true sando that rules them all – you’ll need to visit Tōu, the bready brainchild of Tātā Eatery founders Zijun Meng and Ana Gonçalves.

Tātā Eatery is another of London’s great food stories born from unconventional means, as neither Ana nor Meng are from traditional chef backgrounds. Ana was born and raised in Portugal and worked as a graphic designer before moving to London and enrolling at Le Cordon Bleu. ‘I just got bored with it, I guess,’ she says of her old job. ‘There was no way I could just sit at a computer for eight hours a day.’ Meng’s story is similar – ‘I always loved cooking,’ he explains. ‘I did a fine art degree. After I graduated, I pretty much went straight into the kitchen.’

The pair met whilst working at The Loft – Nuno Mendes' breakout restaurant, based out of his own flat in Dalston – and followed him to Viajante, where his molecular gastronomy and far-out flavour combinations attracted nationwide attention and a Michelin star, among other awards. They both worked at Chiltern Firehouse too, before leaving and starting up their own project. ‘We pretty much only worked for Nuno,’ says Meng. ‘We still keep in touch, he’s like family.’

A combination of time spent with Nuno and the pair’s cultural backgrounds has rather pigeon-holed their food as being Portuguese-Chinese fusion, but they both insist that isn’t an accurate portrayal of their food. ‘When we started Tātā Eatery, everyone picked up on the fact that we were a Portuguese woman and a Chinese man and assumed that we were doing Portuguese-Chinese fusion, but our food is not about that at all,’ says Ana. ‘Those things do come into our cooking but we have lots of other influences too.’ The pair inherited a fondness for Mediterranean produce from their time with Nuno, and both love food from all over Asia. The combination of the two has little to do with their backgrounds. ‘When we started out, we used Portuguese and Spanish produce because it was really good quality,’ says Ana. ‘Not so much anymore though,’ Meng adds. ‘We still use Iberico pork and Spanish anchovies, but ninety percent of our produce is British now.’

The unusual flavours that brought them a huge cult following have little to do with their cultural backgrounds and more to do with their own unique approach to food and imagination. They take influence from Portugal and China, but also Japan, the rest of the Mediterranean and far beyond. Their menus at Tātā Eatery have always revolved around the pair’s mutual love of rice, as well as fresh seafood and lots of fermented ingredients. Tātā first started as a street food stall on Druid Street in Bermondsey before Ana and Meng embarked on a series of residencies at venues like Borough Wines in Kensal Green, Curio Cabal in Dalston and Kitchen Table (at the invitation of James Knappett).

Fast forward to 2019 and Tātā Eatery is one of the most exciting projects in London. The pair have expanded into two permanent sites – a collaboration with world-famous bartenders Monica Berg and Alex Kratena at Tayēr + Elementary in Old Street, and Tōu (pronounced ‘toe’), a restaurant which takes pride of place on the mezzanine of the shiny new Centrepoint Arcade near Tottenham Court Road. The two are vastly different and represent the grand spectrum that Ana and Meng’s cookery can cover. At Tayēr + Elementary, Meng serves a daily changing, five-course set menu for four lucky people at a time at the kitchen counter – ‘I don’t do numbers anymore,’ he deadpans. ‘Just four.’ Tōu is focused more on the magnum opus that shot Tātā Eatery into Instagram stardom – the famous katsu sando.

‘We did a dinner with our friend António Galapito (chef patron of Prado in Lisbon) – he used to be head chef of Taberna do Mercado,’ Ana explains. ‘Meng wanted to do a pork sandwich that was better than the Portuguese bifana, and the result was our very first katsu sando.’ The original went down well enough that the pair kept it on the menu at Tātā Eatery when they returned, and the rest, as they say, is history. ‘It was just another dish to be honest,’ Meng adds. ‘Our menu changes on a daily basis. We knew it would stay on for a bit because we were at Borough Wines at the time – we didn’t have much starch on the menu and it’s food for eating with a drink, but we didn’t know it was going to become this.’

So, what is it that makes the katsu sando at Tōu better than the rest? The devil is in the detail. Firstly there are the obvious things; the Panko-encrusted filling is made using Iberian pork neck – a very specific cut of Iberico pork that provides the perfect combination of texture and flavour. ‘Each pig only has two of the muscles [that make up the neck],’ Meng explains. ‘For our supplier, bringing one tonne of meat for us every month, that's a hell of a lot of pigs. And this is not just any pig – they have to be Iberico.’ Cooking the neck sous vide allows them to get perfect, consistent results time after time, before they breadcrumb and fry it. As we’re chatting, a chef next to us is busy with a special bread slicer, ensuring that every slice of brioche is exactly the same. Consistency is important in any restaurant, but when you’re dealing with a dish that relies on total geometric perfection, it’s everything.

Most will come to Tōu for the katsu, but don’t dismiss the other items. The menu features a smart egg tofu sando alternative, where deep-fried egg tofu sits coddled by a wasabi-spiked egg mayonnaise – like the katsu, it’s more than the sum of its parts. An ox cheek sando has recently hit the menu too, and there are plans for a fourth – as yet unannounced.

Ana and Meng could easily keep banging out their hit single for the rest of their careers and make a good living, but they’re artists – they’re far more interested in creative fulfilment. ‘It would be easy to keep cooking the favourites,’ says Ana, ‘but you’ve just got to keep evolving. Once we’ve made something it’s like, ‘that was great, but now we’re done with it – let’s move on and create something new'.’ The katsu sando might still be top of the charts at Christmas, but Ana and Meng are already working on the difficult second album.