First remove the lobster meat from the shell. Twist the claws off and use a rolling pin to crack them. Carefully remove the claw meat and set aside. Peel the tail and remove the meat. Slice the tail meat and break the claw meat up into pieces. Pick through to ensure you have remove all shell and cartilage, then place in the fridge. Bash the pieces of shell with a rolling pan to break them up

Heat the oil in a large pan over a high heat and add the lobster shells. Cook for 5 minutes, stirring occasionally. Lower the heat to medium and add the onion, carrot, leek, garlic and bay leaf. Stir and cook for another 5 minutes until the vegetables start to colour

Turn up the heat and add the wine, letting it reduce by half. Add 500ml of water, bring to the boil, then reduce the heat and simmer for 30–40 minutes, until the liquid is significantly reduced

Drain the shells in a large sieve over a bowl, pressing down with the back of the spoon to extract as much liquid as possible. You should be left with 100–150ml of intently flavoured liquid. Discard the shells and vegetables and pour the liquid into a jug with the milk

Cook the pasta in a pan of salted boiling water for 2 minutes less than the instructions on the packet, so that it has a slight bite

Preheat the oven to 180°C/gas mark 4

Melt the butter in a large saucepan over a medium heat until foaming, add the flour and whisk for a minute or so to make a roux. Turn down the heat and add the milk mixture a little at a time, whisking continually. Cook gently for 8–10 minutes until the mixture thickens to the consistency of double cream

Add the cheese and stir well until it has melted, then add the lobster meat, the cooked pasta and a pinch of cayenne. Stir and season to taste. Tip into an ovenproof dish approximately 30cm wide and 10cm deep

Mix the breadcrumbs, cayenne and Gruyère together in a small bowl. Sprinkle over the top of the dish and place in the oven for 20 minutes, or until golden brown and bubbling. Serve with a green salad