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Delicious recipe for lobster thermidor

Lobster Thermidor

Celebrate your special day or event grand in style with this Lobster Thermidor recipe. This is an adaptation from the popular French-based bechamel coated lobster chunk with reference to the Julia-Child version.
Course Main dish
Cuisine French
Keyword Bake lobster custard sauce
Prep Time 35 minutes
Cook Time 25 minutes
Total Time 1 hour
Servings 2
Author Victoria


  • 1 lobster ~ 1.4 lb
  • 0.25 cup cognac
  • 1 cup seafood stock
  • 1 egg yolk
  • 5 Tbsp butter unsalted
  • 0.3 cup heavy cream
  • 2 Tbsp shred Gruyère or similar high moisture cheese
  • 0.5 pint mushroom sliced
  • 1 lemon for juice
  • 2 Tbsp flour
  • 0.5 Tbsp powder mustard
  • tarragon, parsley, thyme...
  • green bean optional side
  • salt to taste

Tools needed

  • kitchen shear
  • large crab/nut cracker for the claw
  • metal pick or pointed paring knife


Steam & Handle Lobster

  • Bring a pot/steamer with enough water to a boil. While waiting, prepare a bath of ice/cold water.
  • Once boiling, quickly add the steaming rack/shelf and place lobster in. Cover with lid.
  • Steam for 7-9 minutes or until the outer shelve turns red.
  • Quickly transfer lobster to the icy bath to stop the cooking process and cool it down immediately
  • Have a container ready to pour any gooey or juice coming out along the process. 
  • Use a strong shear to cut the lobster into halves along its length. You can do this easily by snipping the tail flap toward the body into two, then slip the pointed end of the shear into an open hole and start cutting the abdomen shell all the way up to its head.
  • Once done, turn the lobster over and work your shear through the back shell. Carefully extract both sides of the shell out. Clean, pat dry, and set aside.
  • For the claws, just twist/cut them off from the lobster. Bend and break them apart at their knuckles/joints. Use a cracker and pointed paring knife/picker to extract all the meat inside.
  • Cut all the extracted lobster meat into half-inch chunks and add them to the lobster juice container above.

Mix the egg custard & sauce

  • In a small saucepan over low/medium heat, melt 1 tablespoon butter and saute sliced mushroom and 1 teaspoon lemon juice until soft.
  • Add 3/4 of seafood stock to the mushroom, bring to boil then simmer for 10-15 minutes to reduce into half
  • Whisk 1 egg yolk with half a tablespoon powdered mustard and heavy cream.
  • Mix remaining seafood stock with flour, stir well to make sure no residue.
  • Make sure heat is on low/simmering. Pour the flour/stock mixture into saucepan while stirring.
  • Slowly pour the egg/cream mixture in while whisking continuously.
  • Keep whisking until the sauce become thick like custard. Remove saucepan from heat.

Saute the lobster

  • Melt butter in a saucepan over medium heat.
  • Add all the lobster meat/juice into a sauce pan. Stir a couple of times to mix.
  • Pour the cognac all over lobster meat. Bring to boil to vaporize all the alcohol.
  • Sprinkle in some finely minced parsley, tarragon, and other herbs. Also, Spoon in the custard cream sauce.
  • Stir well to combine and remove from heat source.

Cheesy Broil

  • Preheat oven to 425F.
  • Arrange lobster shell onto baking tray/pan. Use foil wrapper to level the shells.
  • Carefully spoon in the lobster meat/sauce mixture into each shell.
  • Sprinkle some finely shred cheese on top.
  • Bake/broil for 10 minutes or until the cheese is bubbling.
  • Once done, carefully transfer to a serving plate. 
  • Serve them immediately with some veggies or bread and fine wine.


Extra sauce is perfectly paired with boiled/steamed green bean and carrot  as dipper.