Chef Mr Tom Brown of Cornerstone in east London shares his three favourite fish recipes.

If you want to experience some of the best fish dishes in Britain, head to Cornwall or, more specifically, Port Isaac where, just a stone’s throw from the sea you will find Restaurant Nathan Outlaw. If you’re not lucky enough to have eaten there, two Michelin stars and a Best UK Restaurant award from The Good Food Guide tell you all you need to know about the skill and respect that go into Mr Outlaw's simple but astonishing cooking.

A new restaurant opened in Hackney Wick, east London, this week called Cornerstone. This is a long way from the ocean and Mr Outlaw’s stars, but chef/owner Mr Tom Brown knows Mr Outlaw and his food only too well, and will be looking to emulate his success. Mr Brown worked at Mr Outlaw’s restaurant in Cornwall for several years and went on to head up Outlaw’s At The Captial in Knightsbridge, London. All of which bodes rather well for Cornerstone, which, says Mr Brown, is a bit of a family affair.

“My grandmother had a big townhouse in Cornwall,” Mr Brown says. “When she died, I asked my aunties and uncles if they would club together for the restaurant. Money’s been tight, but it’s great to be the sole director.”

But what about the food? Lots of fish, we presume. “It would be silly for me to move away from fish,” says Mr Brown. “But I just want to work with the best produce available. Fish isn’t always at its best. When there are amazing vegetables, we’ll do veg dishes. We’ll work with nature and the seasons.”

To give us a little taste of the cooking at Cornerstone, we asked Mr Brown to come up with three simple ways to prepare his favourite fish, mackerel. “It’s the tastiest fish in the sea,” he says. “And they’re stunning to look at.”

“We will be serving up a great raw mackerel dish at Cornerstone. First, the fish has to be super fresh for this to work. Look at the gills. You want them to be nice and bright. The darker the red, the better. The eyes should be prominent, too. Not sunken. And the fish shouldn’t smell fishy. It should smell pleasantly of the sea.

“The dish we will serve is raw mackerel sliced very thinly and dressed with lime zest and juice, olive oil and sea salt. It’s then garnished with homemade lime pickle. You can make this by chopping up limes with oil, spices, garlic, sugar and vinegar and cooking it all down and stirring it. Then we put toasted mustard seeds through it at the end.”

“Mackerel is the perfect fish for barbecuing because it has a high fat content. Fatty, oily fish cooks better on a barbecue. Like pork chops and lamb chops, the fat drips onto the fire and gives a smokiness to the flesh. Mackerel skin goes crispy as well.

“When barbecuing mackerel, you want to keep it as simple as possible. Cooking the fish whole on a very hot grill is the best way. To tell if a fish is cooked, push it with something blunt, like the back end of a spoon. If it goes through without resistance, it’s cooked. A medium mackerel should take two to three minutes on each side. Serve it with some salsa verde, which you can make with herbs, capers, gherkins, garlic, anchovies and mustard.”

“The best way to serve smoked mackerel is in a pâté. Pick up a packet of high-quality oak-smoked mackerel and blend it in a food processor until smooth. Do this with an equal amount of cream cheese (500g, for example), a little horseradish sauce, lemon juice and some black pepper. Spoon it into ramekins and leave to set in the fridge, serve with toasted rye bread and pickled cucumber. Delicious.”