The basis for Thermidor sauce is a traditional French bechamel, which is composed of a light roux with milk added to make a creamy sauce. This one is thicker than usual as it is used to make a filling. We suggest you make additional room for the Thermidor stuffing by pulling the crawlers or front legs from the head region of the lobster shells. Make sure you keep the tail and head portions of the shell intact while removing the meat, as the large half shells make an impressive presentation when stuffed.
- 2 lemons, halved
- 1 onion, quartered
- 1 Bouquet Garni, recipe follows*
- 2 (1 1/2 to 1 3/4-pound) live Maine lobsters
- 2 tablespoons unsalted butter
- 2 tablespoons minced shallots
- 1/2 teaspoon minced garlic
- 2 tablespoons all-purpose flour
- 2 tablespoons cognac or brandy
- 3/4 cup milk
- 1/4 cup heavy cream
- 1/4 teaspoon salt, plus 1/8 teaspoon
- 1/8 teaspoon ground white pepper
- 1/2 cup finely grated Parmesan, plus 2 tablespoons
- 1 tablespoon dry mustard powder
- 1 tablespoon finely chopped fresh tarragon leaves
- 2 teaspoons finely chopped parsley, plus additional for garnish
Preheat the oven to 375 degrees F. Line a baking sheet with aluminum foil and set aside.
Bring a pot of salted water containing the lemons, quartered onion, and bouquet garni to a boil. Add the lobsters and cook until red and firm, 8 to 10 minutes. Transfer the lobsters to an ice bath to stop the cooking process.
When the lobsters are cool enough to handle, cut in half lengthwise with a heavy sharp knife and carefully extract the tail meat. Remove the large claws from the body and gently crack with the back of a heavy knife to extract the meat. Gently pull the front legs from the shell and discard. Dice the tail meat and claw meat and set aside.
Place the halved lobster shells on a baking sheet, cut sides down, and roast until dry, 5 to 6 minutes. Let cool on the baking sheet.
Melt the butter in a medium saucepan over medium heat. Add the shallots and garlic and cook, stirring, until fragrant, about 30 seconds. Add the flour and whisk to combine. Cook, stirring constantly with a heavy wooden spoon to make a light roux, about 2 minutes. Add the cognac and cook, stirring, for 10 seconds. Add the milk slowly, stirring constantly to incorporate. Bring to a boil, reduce the heat, and simmer until thick enough to coat the back of a spoon, 2 to 3 minutes. Slowly add the cream, stirring constantly, until all is incorporated. Cook, stirring, over medium heat for 1 minute. (The mixture will be very thick.) Add the salt and pepper and stir well.
Remove from the heat and stir in 1/2 cup of the cheese, the mustard, tarragon, and parsley. Fold in the lobster meat. Divide the mixture among the lobster shells and place stuffed side up on a clean baking sheet. Sprinkle the top of each lobster with a portion of the remaining cheese and broil until the top is golden brown, 5 minutes.
Place 1 lobster half on each of 4 large plates, garnish with additional parsley, and serve immediately.
*Bouquet Garni is a small bag filled with herbs and seasonings that is used to flavor poaching liquids and broths. By placing the items in a bag, the liquid stays free of debris and the seasonings can easily be extracted. The ingredients in the bouquet garni vary to suit the final dish.
- 1 bay leaf
- 1 small sprig fresh thyme
- 3 sprigs fresh parsley
- 1/2 teaspoon black peppercorns