If you are using fresh mussels and clams, wash them thoroughly, changing the water a few times (mussels in particular need to be scraped and the "byssus thread" or "beard" between the two valves pulled out sharply, not cut). Put them in a deep saucepan with the lid on and, stirring from time to time, heat so that they open. As soon as they have opened up, remove from the heat and leave to cool. Remove them from their shells (leaving about ten of them whole) and filter the cooking water left in the bottom of the saucepan, using a sheet of kitchen paper, into a cup. Put the shellfish and filtered liquid on one side. Next, on a chopping board, chop the prawns, langoustines and squid into pieces, but not too small (you may find it easier to cut them with a pair of kitchen scissors). Now finely chop the garlic, 20 g of parsley and the chilli pepper and sauté them, without letting them brown too much, in a frying pan with 4 spoonfuls of olive oil. Add the chopped seafood, the whole prawns and langoustines, and sauté gently; pour in the white wine, let it evaporate and season with salt. Cook for 10 minutes, add the shelled mussels and clams, turn off the heat and put the lid on the frying pan. Now cook the linguine and strain when still very “al dente”. Put the frying pan back on the heat, remove the whole prawns and langoustines (so as not to spoil them) add a glass of the water the shellfish were cooked in and heat everything well. Tip the linguine into the frying pan and toss, letting the shellfish water evaporate. Turn the heat of and garnish with the mussels, clams, langoustines and prawns that you set aside, the rest of the parsley (chopped) and 2 spoonfuls of olive oil. The recipe is little fiddly to prepare, but these linguine are so delicious and look so good that they will earn your forgiveness for all the hard work!