Chef Nathan Outlaw recently embarked – quite accidentally – on an acting career. Look closely and listen well, and you'll catch the 41-year-old restaurateur in new movie Fisherman's Friends, a film based on 10 singing Cornish fishermen who got a record deal.

Port Isaac-based Outlaw was roped in after a couple of producers knocked on his door, asking if he wanted to be in it. "I thought they wanted people to sit in the background, drinking a pint or something," he recalls, "then I get down there..."

They presented him with a situation: He's parked his car and the tide's engulfed it, what do you do? "I had to react naturally," he says with a laugh, "and I said, 'Oh bollocks!' – and that was my line for the whole film."

However, he's not convinced an acting career is going to usurp his culinary endeavours – "I did one line and it took me eight takes!" – which is understandable, after all he's still the only chef in the UK with a two Michelin star seafood restaurant.

Now, Restaurant Nathan Outlaw has its own eponymous cookbook to match. The recipe collection considers a year in the life of the hilltop restaurant, moving deftly through the seasons as the dining room's views out over the Atlantic shift too: There's the globe artichokes and peas of early spring; baked hake and creamed corn of late summer; monkfish and seaweed for late autumn, and mackerel with pickled onion to usher in winter.

Outlaw calls it a "real snapshot" of what he and his team do, and sees it as an opportunity for people to capture a bit of that at home, even if they can't make the schlep to north Cornwall.

He is particularly fond of the spring chapters. "It's that time of year when you go from having hardly any ingredients, to all of a sudden having lots of different ingredients, which is fun when you love cooking," he muses. Nothing beats the first really good crab that comes in, "when the weather starts to settle down, the fishermen can start to get out," he says. "I love the asparagus. When that starts to show, you really know it's springtime, it marks the season," he adds.

While he does eat stuff aside from seafood at home ("It's a little bit more international," he says, of an average dinner with his wife and two kids), even when he's not on service, he struggles to forsake seasonality. "I can't bring myself to eat asparagus in November from somewhere far-flung. It's a completely different thing I think – it may look like [asparagus], but it's not."

The book is also a reflection of a place and moment in time. It only features dishes that appear on the restaurant menu, and the restaurant relies on produce from Cornwall: "So people might say there's a lot of lobster recipes – well yeah, we're in a port where we get a lot of lobsters!"

You may also notice the absence of some ingredients, which might be because they're "not sustainable any more", or because they're not available, like langoustines and prawns. "I'd love to use them, but you don't get them landed in Cornwall," explains Outlaw, who currently has a new restaurant at The Goring Hotel in London in the works.

However, aside from environmental constraints, the chef says this might be a book bound up with a fine dining restaurant, but the recipes themselves are more than doable in any home kitchen. Although, he admits that what you create "won't be quite the same – what you'll do in the book for two or four people, we have to do for 30 in the restaurant every night".

It helps that he consciously makes his seafood dishes as straightforward as possible though, "so there's no heads and gills and guts, which put people off".

"In terms of the actual complexity of recipes and dishes, they're actually quite simple, that's always been the way I cook," he explains. "You look at it and think, 'It's a nice piece of fish in a sauce', but it's about sourcing that fish, understanding the textural aspects of cooking that fish, and then making the sauce with depth of flavour, and the work that goes into the stock – these are the sorts of things I'm giving away with this book, so people see the amount of work that goes into something that looks so simple."

Kent-born Outlaw – who trained with Gary Rhodes and giant of the seafood world Rick Stein before setting up on his own, first fell for fish not as a foodstuff – but as a connection to the world of the people who haul them in from the ocean.

"I really enjoyed going to the market or down to the seaside to see the boats coming in and out, the fishermen, the hustle and bustle of what they were doing, and I really enjoyed sea fishing," he says, remembering the lure of the harbour-side on holidays as a child – even though when it came to actually eating the catch of the day, it was always battered. "Fish and chips was a treat. I just knew fish that way."

Decades on, whether catching it, cooking it or prepping it, he's still endlessly fascinated with seafood, as well as the fishermen themselves.

"They're very charismatic in their own ways, very unique, very passionate about what they do," says Outlaw. "I like sitting there and having a chinwag with the fishermen. I think they're brilliant, they have so many stories – whether they're true or not, I'm not sure all the time."

l Restaurant Nathan Outlaw by Nathan Outlaw is published by Bloomsbury Absolute, priced £45.