Scampi with chips and tartare sauce

Method

1. Preheat the oven to 220°C/fan200°C/gas 7. Put the chips in a large pan, cover with cold water and add 1 tsp salt. Bring to the boil, then cook for 5 minutes. Meanwhile, drizzle 2 tbsp of the olive oil over a large shallow roasting tray and place in the oven to heat through. Drain the potatoes well, then add to the hot oil, turning to coat. Sprinkle with lots of sea salt and return to the oven for 30-40 minutes until golden and crisp. Toss occasionally and drizzle with extra oil if needed.
2. For the tartare sauce, place the egg yolk in the small bowl of a food processor with the mustard powder, half the lemon juice and some seasoning. Pulse to mix, then add the oil really slowly, drop by drop at first, until the mixture begins to emulsify and you have a lovely thick mayonnaise. Add the remaining lemon juice and taste to see if it needs more seasoning. Scrape into a bowl and stir through the chopped capers, gherkins, parsley and shallot. Taste again and add more of any of the flavourings if you need to.
3. Wash and pat the langoustine tails dry. Put the flour in a bowl, season with salt, black pepper and cayenne pepper, and stir to mix. Crack the egg into a second bowl and lightly whisk. Put the breadcrumbs in a third bowl.
4. Taking each langoustine, dust in the flour, dip to coat in the egg, then roll in the breadcrumbs. Place the coated langoustine tails on a plate lined with baking paper.
5. Heat the oil in a large high-sided pan to 180°C, or until a scampi-size piece of bread turns golden brown and crisp in 2 minutes. Add the scampi with a slotted spoon, cooking in 3 batches, for 2-3 minutes for each batch. Remove and drain on kitchen paper. Serve with the tartare sauce, chunky chips and lemon wedges.