Press the tofu using a tofu press or place it between two clean tea towels, lay it on a plate and put a weight on top. Leave for at least half an hour to drain any liquid and firm up before you start cooking
Once the tofu is pressed, drain away any liquid that’s collected on the plate. Cut the block lengthways down the middle so that you have two long rectangles, then cut across each rectangle to make eight even-sized blocks. You should end up with 16 tofu pieces all the same size.
Make the marinade by cutting the lemon in half and squeezing the juice over a bowl, catching any pips with your other hand. Add the white wine, caper brine and salt and stir to combine. Add the tofu, turning to cover it in the marinade. Set aside to marinate, turning occasionally.
Fill a large saucepan with water and bring to the boil on a high heat. Peel the potatoes and cut them into 1cm-thick chips. Tip them into the water, bring it back to the boil and cook for five minutes. Drain the potatoes, spread them out over a clean tea towel and leave to dry.
To make the batter, put the flour, cornflour, salt and pepper into a mixing bowl and stir to mix. Slowly pour in the ale, whisking continuously so that no lumps form. Set aside once you have a smooth batter.
Use scissors to cut 16 rectangles of nori the same size as the sides of the tofu blocks. Take a piece of tofu out of the marinade and stick one of the nori pieces to it (the wetness of the tofu will help it stick). Hold the nori in place with two cocktail stick. Repeat so that all the tofu pieces have a piece of nori on one side.
Heat the oven to 180°C.
Pour the vegetable oil into a deep saucepan so that it comes no more than two-thirds up the side. Put the pan on medium-high and heat to about 140°C (this is a fairly low temperature for deep-frying so if you don’t have a thermometer, put a chip in the pan to test the temperature: When it’s ready, the chip should float but take a little while to brown).
Put half of the chips in the hot oil and deep fry for three to four minutes, then take them out with a slotted spoon and spread them out on kitchen paper on a plate for a few minutes to cool slightly. Put the rest of the chips into the oil and repeat the process, spreading them over another plate of kitchen paper to cool. Turn up the heat and get the oil really hot, around 180°C (this should make a wooden spoon dipped in the oil sizzle around the edges).
Carefully put the first batch of chips back in the hot oil and fry for four to five minutes, until they’re really golden and crispy. Take the chips out with a slotted spoon and spread over a baking tray. Sprinkle with sea salt and put the tray in the oven to keep the chips warm. Bring the oil back up to 180°C and tip in the second batch of chips. After four to five minutes, remove and spread over a second baking tray.
Get the oil back up to 180°C and line the plates with fresh kitchen paper. Take the nori-lined tofu blocks and dip them into the batter in batches, turning them carefully so they’re completely covered. Carefully drop the battered tofu ‘fish’ into the hot oil and fry for three to four minutes, until they’re dark golden brown all over (you may need to cook them in batches if there isn’t much room and so the temperature of the oil doesn’t drop too low). Remove the tofu ‘fish’ with a slotted spoon and drain on kitchen paper for 30 seconds, then carefully remove the cocktail sticks. Repeat so that all the tofu blocks are double-dipped in two coats of batter.
Take the chips out of the oven and immediately serve on warm plates. Divide the crispy tofu ‘fish’ pieces between the plates and add large spoonfuls of minted mushy peas and tartare sauce. Serve with tomato ketchup and the lemon wedges for squeezing.