The golden, crisp, gruyere-crusted lobster takes center stage on a pristine white plate, its plump, creamy-fleshed meat peeking from a split-open, deep-red shell. Bits of fresh green tarragon add a spark of freshness to the luscious, glossy sauce that pools around the edges.

Aged Gruyere Lobster Thermidor

Name: Aged Gruyere Lobster Thermidor
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Yield: 2 servings
Cuisine: French
Ingredients: 2 (About 1 1/2 pounds each) whole lobster; 1/4 cup butter; 1 small onion finely chopped; 2 garlic cloves minced; 1 teaspoon mustard powder; 1/4 cup all-purpose flour; 1 cup whole milk; 1 cup aged gruyere cheese grated; 2 tablespoons tarragon freshly chopped; 1/4 cup white wine; to taste salt; to taste black pepper; 1 tablespoon olive oil

A luxurious, cheese-crusted lobster thermidor.

Category Main Course

Prep 20 minutes

Cook 30 minutes

Style French

Technique Baking

Diet Friendly Pescatarian

Daily recipe · September 25, 2025

A little about this dish

For National Lobster Day, we're crafting a beautiful Lobster Thermidor with a twist. This French classic is made extra special with the addition of aged gruyere cheese and fresh tarragon. It's a sumptuous treat that will make your Lobster Day truly memorable.

Ingredients (for 2)

Whole lobster — 2 (About 1 1/2 pounds each)
Butter — 1/4 cup
Small onion — 1 — finely chopped
Garlic cloves — 2 — minced
Mustard powder — 1 teaspoon
All-purpose flour — 1/4 cup
Whole milk — 1 cup
Aged gruyere cheese — 1 cup — grated
Tarragon — 2 tablespoons — freshly chopped
White wine — 1/4 cup
Salt — to taste
Black pepper — to taste
Olive oil — 1 tablespoon

Preparation

Step 1 — 🌡️⏱️🔥

Preheat your oven to 375°F (190°C).
Step 2 — 🦞💦🔪

Plunge lobsters in boiling water for about 8 minutes, then plunge in an ice bath. Cut the lobsters in half lengthwise, remove the meat, and chop coarsely.
Step 3 — 🧈🍳🧅

Melt the butter in a skillet over medium heat. Add the onions and garlic, and cook until translucent.
Step 4 — 🍚🥛🍶

Stir in the mustard powder and flour, then gradually whisk in the whole milk. Allow the mixture to simmer, stirring frequently, until it thickens into a bechamel sauce.
Step 5 — 🧀🍷🧂

Add the cheese to the sauce and stir until it has completely melted. Remove from heat, then add the tarragon and white wine. Season with salt and pepper to taste.
Step 6 — 🦞🥄🧀

Ladle sauce into the lobster shells, top with lobster meat, then ladle a bit more sauce on top. Finally, sprinkle with a generous amount of cheese.
Step 7 — 🦞🔥⏲️

Bake the prepared lobsters in the preheated oven for 15-20 minutes, or until the cheese is bubbly and golden.
Step 8 — 🍽️🔥🍋

Serve hot with a squeeze of fresh lemon juice if desired.

A final fox tip

Lobster Thermidor was named after the 11th month of the French Revolutionary calendar, Thermidor. Feel free to make it your own by adding mushrooms or dried herbs. Let children help with stirring the sauce, but always supervise when working with the oven.