Lobster Thermidor needs no introduction, not least from me. A dish renowned for its decadence, it owes its reputation to both its culinary heritage and more pertinently, the cost of lobster, which inevitably side-lines it to high days and holidays.
Preparation of the dish however is no more taxing than mixing cooked lobster in a sauce, returning it to its shell and shoving it under the grill topped with cheese, gratin style. The sauce incidentally is simply a béchamel, prepared in much the same way as any other roux-based sauce, with the addition of brandy, mustard and a dollop of tom’ purée.
The sauce also works very well with crab, which I would choose over lobster any day, not because I’m a cheapskate but because I think it has better flavour, although lobster does have the advantage of its tail meat being one large sliceable hunk. If substituting crab for lobster proceed in exactly the same way, mixing the meat with the sauce and grilling it in the shell. The sauce would also work with a smattering of prawns chucked in and poured over a thick fillet of meaty cod, for example.
A homemade fish stock would be preferable of course; if buying a whole lobster use the legs and the shell from the claws to make it with. Alternatively a regular shop bought stock would also benefit from a quick boil with the shells, and a bouquet garni of fresh herbs. However the following recipe assumes worst case scenario, which is halved and ready dressed lobsters.
Ingredients
(Makes enough sauce for 3 lobsters/ 6 people x half a lobster each)
400ml fish stock
200ml dry white wine
45g plain flour
45g butter
200ml milk
2 teaspoons tomato purée
1 teaspoon Dijon mustard
¼ teaspoon paprika
3 tablespoons brandy
3 tablespoons double cream
1 tablespoon finely chopped fresh tarragon
¼ teaspoon white pepper
1 teaspoon salt
75g grated cheese, Gruyère, Comté or cheddar
Prepare the lobster shell for filling by removing the tail meat and slicing it into 5 or 6 pieces and remove all other meat from the body cavity to a bowl.
Begin by adding the fish stock and white wine to a small pan and boiling the liquid over a medium heat until reduced to 200ml.
Now in the same pan, melt the butter and add the flour to make a roux. Cook briefly over a gentle heat for a couple of minutes and then pour in the milk, whisking continuously. When the sauce is thickened and lump free, whisk in the stock/wine reduction.
Let the sauce simmer gently for a couple of minutes, then add the brandy, cream, tomato purée and mustard. Let the sauce simmer again and then add the salt and pepper in small increments, tasting as you go. Remove the pan from the heat and add the tarragon.
(You could refrigerate the sauce at this point; mix with the lobster meat once it’s cooled to room temperature.)
Pour a little sauce into the bottom of the empty shells, then mix the prepared meat with the remaining sauce and fill the shells equally.
Top each lobster with grated cheese and slide under a preheated grill for 4 or 5 minutes until golden and bubbling.