Lobster Thermidor

published Dec 18, 2022
Lobster Thermidor Recipe

A classic thermidor cooked in a rich cream sauce and topped with melted Gruyère cheese.

Serves2 to 4

Prep40 minutes

Cook20 minutes

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Credit: Laura Rege

Lobster Thermidor is one of those old-school French dishes that doesn’t hold back on decadence and feels like a super-special treat. This is a classic take on the dish — cooked lobster is removed from the shell and claws, cooked in a rich brandy cream sauce, and stuffed back into the lobster shell to finish in the oven with a generous handful of Gruyère cheese. Sure, there are a few steps, but when it hits the table everyone’s awe and enjoyment is going to make it all worth it.

Tips for Making Lobster Thermidor

  • Buy cooked whole lobster. Because the final dish is presented in the lobster shell, you must start with a whole lobster. To make things easier, buy cooked lobster in the shell (you can get them cooked fresh or buy them in the frozen section). Alternatively, you can cook your own.
  • Prep the lobster a day ahead. The lobster meat can be removed from the shells up to a day in advance.
  • Mix in fresh herbs. This step is optional but totally delicious: Mix chopped herbs like parsley and tarragon into the mushroom cream sauce.

Lobster Thermidor Recipe

A classic thermidor cooked in a rich cream sauce and topped with melted Gruyère cheese.

Prep time 40 minutes

Cook time 20 minutes

Serves 2 to 4

Nutritional Info


  • 4 ounces

    cremini mushrooms

  • 1

    medium shallot

  • 1

    large clove garlic

  • 4 sprigs

    fresh parsley

  • 1 sprig

    fresh tarragon (optional)

  • 1

    small lemon

  • 2 ounces

    Gruyère cheese

  • 2

    (about 1 pound) whole cooked lobsters, thawed if frozen

  • 1/2 cup

    heavy cream

  • 2

    large egg yolks

  • 1/4 teaspoon

    kosher salt, plus more as needed

  • 2 tablespoons

    unsalted butter

  • 1/4 cup


  • 1 tablespoon

    all-purpose flour

  • 1/2 teaspoon

    Dijon mustard

  • 1/4 teaspoon

    cayenne pepper


  1. Thinly slice 4 ounces cremini mushrooms (about 1 3/4 cups). Finely chop 1 medium shallot (about 1/4 cup). Mince 1 large garlic clove (about 1 teaspoon). Pick the leaves from 4 freshly sprigs and finely chop until you have 1 tablespoon plus 1 teaspoon. Pick the leaves from 1 fresh tarragon sprig and finely chop until you have 1/4 teaspoon. Cut 1 small lemon into wedges. Grate 2 ounces Gruyère cheese on the large holes of a boxed grater (about 1/2 cup).

  2. Twist the claws off of 2 (about 1-pound) whole cooked lobsters. Crack the meat from the claws and discard the claw shells. Chop the meat into bite-sized pieces and place in a medium bowl.

  3. Halve each lobster lengthwise through the tail: Start at the tail end with kitchen shears. When you reach the head, use a chef’s knife to cut straight down. Remove the meat from the tail, reserving the shells. Cut the meat into bite-sized pieces and add to the bowl of claw meat. Refrigerate until ready to use.

  4. Remove the gills and other parts inside the top half of the lobster so you are left empty shells. Rinse the shells and pat dry with paper towels. Place cut-side up on a rimmed baking sheet (line with aluminum foil first if desired), spacing them evenly apart.

  5. Arrange a rack in the upper third of the oven and heat the oven to broil. Place 1/2 cup heavy cream, 2 large egg yolks, and 1/4 teaspoon kosher salt in a medium bowl and whisk to combine.

  6. Melt 2 tablespoons unsalted butter in a medium skillet over medium-high heat. Add the mushrooms and sauté until tender and starting to brown, about 3 minutes. Add the shallot and garlic, and cook, stirring occasionally, until the shallot and garlic are tender and fragrant, about 2 minutes.

  7. Carefully pour in 1/4 cup Cognac and bring to a boil. Boil until almost evaporated, 1 to 2 minutes. Add 1 tablespoon all-purpose flour and cook, stirring constantly, until the flour is lightly toasted, about 1 minute.

  8. Add the egg yolk mixture and bring to a simmer, scraping up the browned bits from the bottom of the pan with a wooden spoon. Reduce the heat to medium and simmer, stirring constantly, until slightly thickened, 1 to 2 minutes. Add the lobster meat, tarragon, 1 tablespoon of the parsley, 1/2 teaspoon Dijon mustard, and 1/4 teaspoon cayenne pepper. Stir to combine. Taste and season with kosher salt as needed.

  9. Remove the pan from the heat. Add half of the cheese and stir to combine. Spoon the lobster mixture evenly into the lobster shells (about 1/2 cup each). Sprinkle with the remaining cheese.

  10. Broil until the cheese is melted and golden brown, 4 to 5 minutes. Garnish with the remaining 1 teaspoon parsley and serve with the lemon wedges.

Recipe Notes

Make ahead: The lobster meat can be removed from the shells up to 1 day in advance. Refrigerate the meat and shells in airtight containers.

Storage: Leftovers can be refrigerated in an airtight container for up to 2 days.