The Michelin-starred Swede gives us the recipe for his Nordic-meets-New York signature style .

They say you should never trust a skinny chef. By that rationale, you’d run a mile from Mr Fredrik Berselius. The 38-year-old Swede doesn’t have an ounce of fat on him, partly down to genetics (he used to model), partly down to the fact that when he’s not helming the kitchen at one of New York’s finest restaurants, he races competitively with the Rapha Cycling Club (he even shaves his legs).

Mr Berselius’s restaurant, Aska, has been open in its current location right underneath Williamsburg Bridge in Brooklyn for one year this week. Within four months, it was awarded two Michelin stars. The unassuming, unmarked restaurant has just 10 tables and is open only for dinner, a wildly inventive three-hour, 19-course tasting menu that is a model of sustainability. This goes not just for the ingredients, which the chef sources locally – some foraged in and around his 27-acre property in the Catskills in Upstate New York, others organically grown in the riverside urban farm just 100m from his restaurant – but also in terms of working conditions. Mr Berselius’ kitchen staff work hard, but, unusually for New York, the restaurant’s $250 (£192) menu (or $175 10-course menu) includes a built-in service charge, allowing him to pay all staff a living wage, while eliminating the common confusion and uncertainty around tipping.

The restaurant is closed on Sundays and Mondays to give the team a chance to recharge. “I know so many people in this industry who just burn out,” says Mr Berselius. So, after service finishes on a Saturday night, Mr Berselius and Katrina, his wife of 12 years, often drive three hours up to their house in the Catskills where they are putting the finishing touches to the Aska cookbook. “For me, it’s necessary to get away at weekends and clear my head,” says Mr Berselius. He has built up relationships with local farmers in the Catskills, but he also enjoys foraging on his own land, a mixture of meadows, forests and streams. “One of my biggest inspirations in life is my grandfather, who taught me about nature,” he says.

“I remember growing up in Sweden and strolling through the woods with him. He would say, ‘You can nibble on this’ and ‘You can eat that.’ And that’s how it started. If you get an early introduction to wildlife, it sort of sticks with you.”

They return on a Tuesday, laden with unusual ingredients for that week’s menu, such as lichen scraped from rocks for his signature reindeer moss dish, or aromatic grasses in which to smoke langoustines.

Mr Berselius spends much of his week wearing his white chef’s jacket and black apron. Off duty, he admits that black tends to be his default setting. “I have so much going around in my head and so many decisions to make each day, it just saves time and energy to keep some things simple,” he says. “A typical outfit would be black Acne jeans, black Common Projects sneakers, black Theory T-shirt.” Although, like any good chef, Mr Berselius recognises the importance of seasonal ingredients, once he’s found a recipe that works, he sticks with it. Even his dining room with its spotlit open kitchen is completely black. “Maybe it’s a Swedish thing, or maybe it’s a New York thing, but I don’t wear a lot of bright colours and patterns,” he says. “My colour palette is dark and moody: black, greys, olive green, navy.” And he tends to favour Scandinavian brands “because they suit my aesthetic and physique”.

Mr Berselius works in his restaurant five nights a week, but in the mornings he cycles, sources produce, takes meetings and works on his book. Here he takes us on a tour of his regular haunts around Williamsburg in Brooklyn.

Aska

“My mother was an amazing home cook, but it was actually my sister, Michaela, who first opened my eyes to the restaurant industry. [She runs restaurants in Edinburgh with her husband, the Michelin-starred chef Mr Tom Kitchin.] Aska means ashes in Swedish – I just like the name. A lot of my food is based on memories and flavours connected to Sweden, but we cook mainly with ingredients from this region, so I’d say we’re a New York restaurant with Nordic roots. I’m interested in foods you won’t see at most places, food that makes you think, that stimulates more than just your taste buds. There is one dish on the menu, which is lamb heart that has been cured, then grated, then burnt in the grass that grows on the hills in upstate New York. The inspiration came after watching the incredible fiery sunsets you get up there. You can imagine the sheep walking into the sun and catching fire.

“This is the courtyard at the back of the restaurant [pictured below] – we grow some herbs here and serve drinks and small plates out here. I don’t usually dress up during the day unless I am going to a lunch event, but I do like suits. With my frame, slimline tailoring works best. I like the trousers to finish just on the shoe – in this case, a really chunky-soled derby from Dries Van Noten in burgundy pebble-grain leather.”

Williamsburg Bridge

“I love the mornings when I manage to get up at 5.30am and get on my bike. The first thing I put on is my cycling kit and head out for two hours before coming home to have a simple breakfast with my wife, Katrina, who helps run the restaurant with me. We’re looking for a place in Brooklyn closer to the restaurant, but at the moment we live on the Upper East Side and riding around Central Park is just perfect before 7.00am, when they open it to traffic.

“I have a regular crew that I cycle with. I’ll often ride to and from the restaurant over the Williamsburg Bridge. It’s the quickest way to get to work. I’ve always been into cycling. My first job after school was as a bike courier in Stockholm. I find cycling quite meditative in a way, but I do really push myself and I still race. I’m competitive with myself by nature. The same goes for the restaurant. We really push ourselves there to be as good as we can be.”

North Brooklyn Farms

“We have a plot at an urban farm literally two minutes’ walk from the kitchen where we grow a lot of the greens and herbs that we use at the restaurant on a daily basis. There aren’t just four seasons, there are 52 micro-seasons. Every day things change. At the moment we have bronze fennel, different types of sorrels, different succulents, some sunchokes. We have dill, camomile, salad burnet, nasturtiums, various edible flowers. I like to come down here in the morning before service and pick what we need for that evening.

“If I know I’m going to be getting into the patch, I’ll put on my boots – these rubber-soled Chelsea boots from R.M.Williams are called Gardener boots – together with some jeans and a military jacket. It’s great for me and the staff to be connected to what’s growing right now, how plant life works, how it should be a fundamental part of cooking. This farm is often open for the public to visit, a patch of green space in a very built-up environment, so it’s a nice place to sit for a moment and look out across the river.”

The Four Horsemen

“One of the things that is special about Aska is that all the chefs – myself included – serve the guests the dishes they have prepared and introduce them. It’s part of the dining experience, but it’s also good for the chefs to have that direct interaction. We have an open kitchen and I think people, whether they are repeat customers or visitors from overseas, like to see the team at work, very hands on.

“People often ask me where else they should try in the area. Unfortunately, because I work every night I don’t have as many recommendations as I should, but I always send people to The Four Horsemen, which is nearby. It’s open until 1.00am, so sometimes I will throw on a nice jacket so we can grab a quick drink after service. It’s become a neighbourhood standby. James Murphy, the lead singer of LCD Soundsystem, is one of the owners and my friend Nick [Curtola] is the head chef. It’s a friendly little neighbourhood wine bar with delicious small plates and they always have good music. I wish I could come here more often. Maybe soon I will try and take a night off every now and then. Maybe.”

Jane Motorcyles

“In the summer, I basically live in these Theory shorts, and Common Projects are my go-to sneakers. I feel at home in this part of Brooklyn, which is why I wanted to open my restaurant here, even though it took me two years to find the right space. I deliberately chose a street that is a bit off the main drag and the restaurant has very subtle signage, so the experience starts even before you come through the door.

“Williamsburg has changed a lot, but the businesses around here shape the neighbourhood and I like that, for the most part, they are small, independent and passion-driven. We try and support each other, form a community. Jane Motorcyles, for example, is a bike shop that serves great coffee so you’ll often see bike enthusiasts gathering out front, tinkering with their vintage Triumphs as the regulars come in for their cappuccinos. It’s just around the corner, so I’ll often stop in to grab an espresso, take a meeting or try and find some time to work on the Aska cookbook, which is due very soon.”