- a large lobster - at least 600g (or two small). If raw, you'll need to cook it before you start making the Thermidor.
- 1 tbsp oil
- 45g/1½ oz butter
- 2 shallots, finely chopped
- 100ml/3½ fl oz dry white wine
- 1 tsp each chopped tarragon, chervil and parsley
- 150ml/5 fl oz double cream
- 1 tsp French mustard
- ½ tsp paprika
- 4 tbsp freshly grated Parmesan or Gruyere cheese
For the bechamel sauce
- 290ml / ½ pt milk
- bay leaf
- 5 peppercorms
- a blade of mace
- one slice of onion
- 20g/1oz butter (melted)
- 20g /1oz flour
- If using a raw lobster, cook it in fast-boiling water. Add lobster and start timing from when the water returns to the boil. Use a lid. Eight minutes for a 500gram lobster, 10 minutes for a 1000 gram fish. Plunge into cold water to cool.
- Make bechamel sauce: heat milk gently with bay leaf, mace, peppercorns and onion. When it simmers, strain and discard flavourings.
- In emptied pan, blend the flour into the melted butter and simmer for 2-3 minutes.
- Slowly add milk, stirring at first then whisking in the last half. Cook for five minutes on a low heat, whisking several times. Keep warm.
- Remove and crack the lobster claws, take out the meat and dice it. Split the lobster in half lengthwise, remove the tail meat, chop and add to claw meat.
- Heat the oil and butter, then cook shallots over a gentle heat until transparent. Add the wine, boil rapidly until reduced by half.
- Preheat the grill to its highest setting.
- Add the herbs, bechamel sauce, cream, mustard and paprika to the pan. Bring to boil, reduce heat and simmer for 2-3 mins or until the sauce is a creamy consistency. Season to taste.
- Put some of the sauce into the base of the shell, then the meat, then another layer of sauce. Sprinkle cheese over the top and grill until hot and bubbling, and the cheese has browned.