New England-style clambake

Method

1. Soak the clams and mussels and heat the oven to 200°C/180°C fan/gas 6. Cut the potatoes into large chunks, put them in a large saucepan with plenty of salt and cover with boiling water. Simmer for 7-8 minutes, then drain and steam dry for a minute or so.
2. Pour the oil into a large roasting tin, then put it in the oven for a few minutes to heat up. When the oil is shimmering, carefully tip in the potatoes and add the corn. Toss everything around to coat in the hot oil and season with pepper. Roast for 1 hour, turning occasionally.
3. After the veg has been in the oven for 30 minutes, prepare the shellfish. Rinse the langoustines, drain and rinse the clams and mussels, then put them in a third large roasting tin – preferably one that fits the whole width of the oven. Cut sheets of foil and baking paper long enough to cover the roasting tin.
4. Put the wine and 75g butter in a saucepan and bring to a simmer. Turn up the heat and boil until the butter has melted, then pour over the langoustines, clams and mussels. Working quickly, cover the contents of the roasting tin with baking paper, then enclose with the sheet of foil, scrunching at the edges to seal them tightly.
5. Put the tin in the oven and cook for 20 minutes. By now the clams and mussels should be open and the langoustines should be piping hot with opaque flesh. If a lot of clams and mussels are unopened, give them a good stir and put back in the oven, uncovered, for 5 minutes more, shaking now and then.
6. Meanwhile, mix all the mayonnaise ingredients together in a bowl, taste, season and set aside. Melt the 100g butter very slowly over a low heat. While it’s melting, set a sieve over a bowl and line with kitchen paper. Once the butter has fully melted, pour it into the sieve, letting the white solids stay behind at the bottom of the pan. Add the chilli and lemon to the strained butter along with some salt, then sit the bowl in warm water to keep the mixture liquid.
7. To serve, either mix the shellfish, potatoes and corn together and serve in individual bowls with some of the juices poured over, or put everything on a big platter or board and put in the middle of the table for people to tuck in. Pour the seafood juices into a bowl and serve with a spoon for people to drizzle over. Serve with the mayo, chilli and lemon butter, and hunks of bread.