📝 About This Recipe
Originally created in 1894 for the opening of the play 'Thermidor' at the Comédie-Française, this dish remains the ultimate expression of culinary luxury. Succulent lobster meat is poached, diced, and folded into a rich, velvety Cognac-infused Mornay sauce before being broiled to a golden perfection in its own shell. It is an opulent marriage of sweet Atlantic seafood, piquant Dijon mustard, and earthy Gruyère cheese that defines fine dining elegance.
🥗 Ingredients
Main Lobster Preparation
- 2 pieces Live Maine Lobsters (approximately 1.5 lbs each)
- 4 quarts Court Bouillon (Water, Salt, Lemon, Bay Leaf) (for poaching)
The Thermidor Sauce
- 4 tablespoons Unsalted Butter (high-quality European style preferred)
- 2 pieces Shallots (finely minced)
- 1/2 cup Fresh Button Mushrooms (very finely chopped (duxelles style))
- 3 tablespoons Cognac or Brandy (for deglazing)
- 2 tablespoons Dry Sherry (optional but recommended)
- 3 tablespoons All-Purpose Flour
- 1 cup Heavy Cream (room temperature)
- 1/2 cup Lobster Stock or Fish Stock (chilled)
- 1 teaspoon Dijon Mustard (adds essential piquancy)
- 1 Egg Yolk (beaten, for richness and color)
- 1 tablespoon Fresh Tarragon (finely chopped)
- 1 pinch Cayenne Pepper
The Gratin Topping
- 1/2 cup Gruyère Cheese (finely grated)
- 2 tablespoons Parmigiano-Reggiano (freshly grated)
- 1 tablespoon Fresh Parsley (for garnish)
👨🍳 Instructions
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1
Bring a large pot of salted water (the Court Bouillon) to a rolling boil. Submerge the lobsters head-first and cook for 8-10 minutes. They should be bright red but slightly underdone, as they will cook further under the broiler.
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2
Immediately transfer the lobsters to an ice bath to stop the cooking process. Once cool enough to handle, split the lobsters in half lengthwise using a heavy chef's knife, starting from the head down to the tail.
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3
Remove the tail meat and claw meat carefully. Discard the grain sac near the head and the intestinal vein. Clean the empty shells thoroughly and pat them dry; these will be your serving vessels.
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4
Cut the lobster meat into bite-sized 1/2 inch chunks. Cover and set aside in the refrigerator.
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5
In a medium saucepan over medium heat, melt 2 tablespoons of butter. Add the minced shallots and mushrooms. Sauté for 5 minutes until the moisture from the mushrooms has evaporated and the shallots are translucent.
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6
Pour in the Cognac and Sherry. If using a gas stove, you can carefully flame it, or simply simmer for 2 minutes until the liquid is reduced by half.
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7
In a separate small pan, make a blond roux by melting the remaining 2 tablespoons of butter and whisking in the flour for 1-2 minutes without browning it.
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8
Gradually whisk the lobster stock and heavy cream into the roux. Simmer gently for 5-8 minutes until the sauce thickens enough to coat the back of a spoon.
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9
Whisk in the Dijon mustard, tarragon, and cayenne. Season with salt and white pepper to taste. Remove from heat.
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10
Temper the egg yolk by adding a spoonful of the hot sauce to the yolk, whisking quickly, then stirring the yolk mixture back into the main sauce. This adds a beautiful golden sheen.
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11
Fold the reserved lobster meat into the sauce, ensuring every piece is generously coated.
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12
Place the cleaned lobster shells on a baking sheet. Spoon the lobster and sauce mixture evenly into the tail and head cavities of the shells.
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13
Sprinkle the grated Gruyère and Parmigiano-Reggiano over the top of each filled shell.
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14
Place under a preheated broiler for 3-5 minutes, watching closely, until the cheese is bubbling and develops deep golden-brown spots.
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15
Garnish with fresh parsley and serve immediately while piping hot.
💡 Chef's Tips
Always use fresh, live lobster for the best texture; frozen lobster can become rubbery when double-cooked. Do not skip the tarragon—it provides the classic French 'anise' note that cuts through the richness of the cream. If the sauce feels too thick, add a tablespoon of stock or cream to loosen it before filling the shells. Ensure the mushrooms are chopped very finely so they integrate into the sauce rather than standing out as large chunks. To keep the lobster shells steady on the plate, nestle them on a bed of rock salt or crumpled parchment paper.
🍽️ Serving Suggestions
Pair with a crisp, chilled glass of Chablis or a vintage Champagne to balance the rich sauce. Serve alongside steamed asparagus spears or haricots verts tossed in lemon butter. A side of saffron-infused rice pilaf is perfect for soaking up any extra Thermidor sauce. Follow the meal with a light lemon sorbet to cleanse the palate after such an opulent dish.