Lobster Thermidor

Lay each lobster on its back and split it lengthways through the head and tail with a heavy knife.

Lift the tail meat out of each half and pick the claw meat from the cracked claws.

Discard the gritty sac behind the eyes and the dark intestinal thread, and keep the shells.

Cut all the meat into 2cm pieces.

Melt the butter in a frying pan and cook the shallots gently for 3 minutes.

Add the mushrooms and cook for 5 minutes, until their water has gone.

Take the pan off the heat, add the brandy, then return it and let it bubble away almost completely.

Pour in the wine and simmer until reduced by half, about 4 minutes.

Add the cream and simmer for 4-5 minutes, until it coats the back of a spoon.

Take the pan off the heat and stir in the mustard and the salt.

Fold the lobster meat and the tarragon through the sauce.

Heat the grill to its highest setting.

Set the four shell halves on a tray and spoon the mixture back into them.

Mix the Gruyère and breadcrumbs and scatter over the top.

Grill for 2-3 minutes, close to the element, until spotted brown and bubbling.