Fish & chips with tartare sauce

In a large bowl, mix the flour, salt, baking powder and 300ml cold water; leave in the fridge to rest for 30 minutes – it should be quite thick once rested. Meanwhile, make the tartare sauce: mix all the ingredients in a bowl, then season if needed; cover and chill until ready to serve.

Cut the potatoes into 1.5cm-wide chips. Bring a pan of salted water to the boil and add the potatoes. Cook for 10 minutes, then drain and leave to cool in the colander. Preheat the oven to 200ºC, gas mark 6. Divide the chips between 2 large baking trays and drizzle with 4 tbsp oil; season with salt and roast for 45 minutes, turning occasionally until golden all over. To keep the chips extra crisp, drain them on a plate lined with kitchen paper before serving.

Meanwhile, put the remaining oil in a large, wide frying pan set over a high heat, until it comes up to 180ºC on a thermometer (you can also test this by dropping in a small piece of bread; if it turns golden after 10 seconds, the oil is hot enough). Be very careful – if it starts to smoke, take it off the heat immediately. Line a baking tray with kitchen paper. Working 1 at a time, season a fish fillet with salt and dredge in the rested batter, then carefully place in the oil. Cook for 3 minutes on one side, then use tongs to turn and cook for another 3 minutes on the other side. You want the fish to be golden brown on both sides, cooked through and opaque (the internal temperature should be 55ºC, and the fish should flake easily with a fork). Carefully transfer to the lined tray and immediately sprinkle with a few sea salt flakes. Repeat with the remaining fillets. Serve immediately with a pile of chips and the tartare sauce.