Snap the claws and smaller legs away from each lobster. Cut the main section in half lengthways using a large chef’s knife, and scoop the contents of the head cavities into a bowl, then remove the dark vein from the tail meat and discard. Remove the tail meat, chop into large chunks and put in another bowl. Lay the empty shells cut-side up on a baking tray and set aside.

Crack the claws and knuckles, then pick out all the meat using a skewer or lobster pick. Roughly chop and add to the bowl with the tail meat. Put any shards of shell into the bowl with the head meat. Use a rolling pin to roll along the length of the small, spindly legs and push out the meat, then tip into the bowl with the claw and tail meat. Again, put any broken shells into the bowl with the head meat. The lobster can an be prepped up to a day before. Cover and chill the meat and broken shells until needed.

To make the sauce, heat the butter in a large saucepan over a medium heat and cook the shallots for 5-6 mins until soft and golden. Add the broken shells and head meat, then turn up the heat and cook for 2 mins more. Splash in the wine or vermouth and bubble for 2 mins to reduce. Pour over the stock and cream, bring to the boil, then continue to cook for 10-12 mins until the mixture has reduced and thickened. Turn the heat off and leave to cool slightly, then pour into another saucepan through a fine mesh sieve, pressing the shells and meat against the mesh with the back of a spoon to extract all the sauce. Stir in the mustard and lemon juice, then taste for seasoning. The sauce can be made the day before, covered and kept chilled.

Heat the grill to high. Spoon the claw and tail meat into the empty reserved shells. Reheat the sauce over a low heat until warmed through, if needed, then stir through the herbs. Spoon the sauce over the lobster meat in the shells, then sprinkle with the parmesan and put under the grill for 4-5 mins until the sauce is bubbling and the cheese lightly golden. Serve with chips or boiled small potatoes and a green salad.