For the ravioli, heat a large frying pan over a medium heat. Add the butter and langoustine shells and fry for 5-6 minutes. Add the carrots and thyme and fry for 3-4 minutes.
Add the brandy, allow to heat briefly, then light with a match. Let the flames flare up then die down. (CAUTION: Keep your face and hair away from the flames. Do not leave the pan unattended.) Cook for 2-3 minutes, then add the stock. Bring the mixture to the boil and cook for 20 minutes. Strain the sauce into a clean saucepan, add 110ml/4fl oz cream and cook for a minute. Season to taste.
Put the flour and three eggs in a food processor and pulse until it forms small crumbs. Tip the mixture onto a lightly floured work surface and bring together to form a dough. Knead lightly for 2-3 minutes, or until smooth and elastic. Wrap in cling film and chill in the fridge for 20 minutes.
Meanwhile, blend the salmon and remaining cream to a purée in a small food processor. Season with lemon juice, salt and pepper.
Place the pasta dough on a clean, flat work-surface dusted with flour, then roll out to a thin rectangle and sprinkle with more flour. Divide the dough into two pieces, then pass each piece through a pasta machine several times, gradually reducing the thickness until you reach the thinnest setting and the pasta feels elastic. Cover any dough that you are not using with cling film so that is doesn’t dry out.
Lay a sheet of pasta on the work surface and place spoonfuls of the salmon mixture at equal intervals along the sheet, leaving a gap of 6cm/2½in between each pile. Spoon out eight piles of salmon and top each pile with the langoustine meat.
Beat the remaining egg. Lightly brush the egg around the salmon and langoustine piles. Top with the second sheet of pasta and press down lightly around the edges of the langoustine. Using a 6cm/2½in pastry cutter, stamp out eight ravioli rounds.
Bring a large pan of salted water to the boil and cook the ravioli for 1-2 minutes, or until they float to the top of the pan. Drain, then mix with the chervil and olive oil and season.
For the grey mullet, heat a medium frying pan and add the oil. Once hot add the fish skin-side down and cook for 2-3 minutes on each side. Transfer to a plate and rest for 10 minutes.
For the broad beans, heat the frying pan until hot, add the butter and the broad beans and fry for 2-3 minutes, or until just softened. Season to taste with salt and pepper.
Meanwhile, blanch the asparagus in a saucepan of boiling salted water for 2-3 minutes, or until tender. Reheat the sauce gently.
To serve, spoon the broad beans into the centre of plates, top with the ravioli and asparagus, pour over the sauce and garnish with some cress.