IF YOU WERE asked to describe Japanese cuisine, chances are your mind would go straight to sushi. Kurobuta, the restaurant from Nobu's Australian former head chef Scott Hallsworth, takes a different approach, and removes the stiff formality from a food that has a reputation in London for being as precise, subtle and rooted in tradition as the culture it was born out of.

Kurobuta started as a pop-up in Chelsea two years ago and now has two permanent sites, various residencies and will potentially be doing a pop-up world tour. Hallsworth's inspiration, he says, comes from Japanese food itself: "It's like meeting someone and falling in love." We chat to him as Kurobuta begins a prestigious residency on Harvey Nichols' fifth floor.

When did you decide that you wanted to go into cooking?

When I was about 14 or 15, my mum used to make me go down to the local Chinese restaurant to work for free on Saturday afternoons. She wanted to instil a bit of a work ethic into me, so I wasn't just hanging around playing drums and guitar with my mates.

Scott Hallsworth

Australian chef Scott Hallsworth

Do you think you would have gone into music if you weren't a chef?

I would like to have. I still try to fiddle around with stuff. I recorded five songs recently with my brother who's a talented musician. He's been recording and writing music since the mid-1980s. He was visiting London recently and we hung out and played. I'm a pretty basic drummer but he's an amazing musician. We ended up recording about five tracks. I like to think I would have gone into music, but I was actually quite a fast runner in school and I was racing at national level, so I probably would have gone into racing at some stage.

Will we be seeing a debut album from the Hallsworth brothers anytime soon?

We did one nearly 20 years ago! We put out a cassette of these interesting, quirky recordings under the moniker of Wild Palms. I'd love to be able to get it out there, but my brother probably might not think it's good enough. He's got quite a high standard so it was probably just a bit of fun.

Why did you decide to go into Japanese cuisine?

People ask that and I can only really say that it's just like meeting someone and falling in love – you didn't think you would ever fall for that person. It's the same with food. For me, I was always into cooking, and then I sort of dabbled with it a little bit, the Japanese stuff, and then I happened to work at Nobu and then after the first few weeks, I went, 'Jesus – this is it for me, I never want to turn away from this.' I love it and there's so much to explore. The road can be rocky, just like a relationship, but it's just part of me now.

Why did you decide to come to London?

I'd always wanted to come to London because that's where everyone came to have their schooling, if you like, their arse-kicking in cooking. On the other side of things, my dad's English and I just thought it would be nice to see where he came from. He's not from London, but I thought it would be nice to get to England anyway.

Kurobuta favourites – in pictures

Your restaurant takes a classically authentic national cuisine and subverts it. Do you think that's becoming a trend?

What is a trend really? I wouldn't be able to tell. Things come and go. Since we've been doing it, I've noticed more people doing it, for whatever reason. It could be a trend now, I have no idea. It could be that other people have realised that Japanese cuisine is extremely popular here in England, here in London at least, and making it a little bit more approachable and or affordable for the big-market customer makes good business sense.

It's also a little bit more fun. A few years ago, everyone was trying to do a Nobu replica. Everyone was running around and it happened over and over and over again, and a lot of them failed, or they did really shitty versions. But people got sick and tired of that, and I think chefs got sick and tired of that as well. Izakaya (Japanese drinking dens that also serve food) cuisine is so much more fun to work with. Day to day, I get stuck into it and I really love it.

Is the food at your Harvey Nichols residency going to differ from your other restaurants?

It's definitely going to mix it up a bit. It's already got 12 newer dishes. And we want to target Harvey Nichols' massive lunch crowd with an izakaya burger and a tempura set lunch. We'll be able to do a really, really good sushi lunch there. When it comes to putting these dishes on the menu at Kurobuta, I don't know! I'll just see how I feel. I think you have a relationship with a dish – you work with one ingredient for a while and then it's like you never want to see it again. The dishes that really work will end up in Kurobuta. Who knows how they'll shape up?

People were spending over £100 a head and we couldn't even give them a seat

I've heard rumours that you'll be doing a pop-up world tour...

It ties into the marketing which I have to do with my book coming out next year, if I ever manage to finish writing it. When that comes out, I'll have to do book signings in New York and Sydney, and London obviously, and maybe somewhere else, if there's a foreign language edition.

I think signings can be as boring as hell, and any clown could do it, so I think we should put a bit more effort in. Food is about tasting it and we're good at doing pop-ups – we made the first Kurobuta happen in four and a half days with hardly any money, and we've travelled the world smuggling sauces in and this and that – so I think we can make a world tour happen, and it should happen around the book. That's the plan at this stage, so that people can really engage with the book better.

Kurobuta's pork belly buns

Kurobuta's pork belly buns

What's the difference between running a pop-up and running a restaurant?

People are far more lenient with you when you call it pop-up, you can get away with anything. I've run out of wine, or I've run down to one bottle of red and one bottle of white in terms of variety, and the customers were completely lenient! People used to fall down our stairs all the time because they were too small. Even a year after we'd been open, and we weren't really a pop-up anymore, we had people who'd stand up to eat. They'd say, 'We'd do anything to eat here,' and I said, 'All you can do is stand at the bar, you can't sit down.' They'd spend a fortune, you know, I'm talking about over £100 a head to get the cocktails and the shots in and we couldn't even give them a bloody seat.

I think people engage in the whole spirit of the pop-up, it invokes something fun and short term and it's limited, and that perception changes things completely. When you're restaurant you've got to pay attention to every single detail and the complaints department has to open up. People send you emails saying things like, 'I went into the toilet and there was a torn poster on the wall.' Before they would have thought it was hilarious and tweeted about it. The customer perception forces you to then pull up your socks, maybe quite rightly so, and become slightly more polished.

What's your favourite of your own dishes?

My favourite dish is the pork belly bun, and I suppose that's because it's what I would eat every time at Kurobuta if I'm hungry. It's not a fancy dish, there's nothing extremely difficult about it. It's a very honest, simple dish.

I think that starts to describe the way I like to approach food these days, as opposed to being quite 'cheffy' a few years ago and thinking about loads of different garnishes and dressing it up, and having bubbles and caviar all over it. I think it's just the way I want to approach food now, because it's so edible. ■

Kurobuta at Harvey Nichols, Fifth Floor Restaurant, Harvey Nichols, 109-125 Knightsbridge, SW1X 7RJ. For more info: harveynichols.comkurobuta-london.com. Like the sound of Scott's food? Try making his tea-smoked barbecue lamb.