Demystifying the Differences Between Lobster Mornay and Lobster Thermidor

As a seafood lover I’ve always been fascinated by the wonderful world of lobster dishes. Lobster is such a versatile ingredient that can be prepared in endless ways yet two of the most popular lobster recipes seem to cause the most confusion – Lobster Mornay and Lobster Thermidor. If you’ve ever pondered over what really sets these two dishes apart, you’re not alone. I did too, which led me to do a deep dive into discovering the key distinctions between these two lobster classics.

In this article, I’ll share my learnings to help demystify the differences between Lobster Mornay and Lobster Thermidor once and for all Whether you’re a home cook looking to attempt these dishes or simply curious to learn more, read on to have all your questions answered!

A Quick Primer on Lobster Mornay and Lobster Thermidor

First let’s start with a quick refresher on what each dish actually is.

Lobster Mornay features lobster meat in a creamy, cheese-infused béchamel sauce, often with the addition of egg yolks, cream, and seasonings. The sauce is then baked or broiled briefly to form a golden, gratineed crust on top. Lobster Mornay is usually served still hot in the lobster shell.

Lobster Thermidor consists of lobster meat that is sautéed separately in butter. A rich sauce is then made with egg yolks, cognac or sherry, and cream, along with seasonings like mustard, salt, and cayenne pepper. The lobster meat is then placed back into the shells and topped with the sauce before being broiled or baked. Parmesan cheese is also sometimes added as a finishing touch.

Now that we have the basics down, let’s explore some of the key differences between these two delicious lobster dishes:

The Sauce Sets Them Apart

The most noticeable difference between Lobster Mornay and Lobster Thermidor is in the sauce.

Lobster Mornay features a béchamel sauce as the base. This classic French white sauce is made from a butter roux and milk. It has a creamy, velvety texture from the milk and butter. Cheese, usually Gruyère or Parmesan, is added to enrich the sauce. Egg yolks are also commonly incorporated for extra richness and body. The end result is a sauce with a lush, creamy mouthfeel.

Lobster Thermidor relies on a sauce made from egg yolks, cream, cognac or sherry, and seasonings. This gives the sauce a bold, complex flavor from the brandy or wine. The egg yolks and cream provide a silky richness and sheen. While cheese can be added as a garnish, it’s not integral to the sauce itself. Overall, the sauce has a more luxurious, custard-like consistency compared to the velvety bechamel base of Lobster Mornay.

Cooking Methods Create Different Textures

Another key difference is the cooking method used for each dish, which impacts the final texture.

Lobster Mornay is often baked or broiled briefly after the lobster meat and mornay sauce are combined. This helps form a browned, crusty top layer on the sauce, providing texture contrast against the creamy interior.

Lobster Thermidor involves sautéeing the lobster meat separately before mixing it with the sauce. The meat retains a tender, juicy texture. Since the lobster shells are filled with the meat-sauce mixture and only broiled or baked briefly at the end, the interior remains lush and silky without forming a crust.

So Lobster Mornay develops more of a contrasting crunchy top from the high heat, while Lobster Thermidor maintains a uniformly supple, custard-like texture throughout.

Flavor Profiles Are Quite Different

Since the sauces are the star of the show, Lobster Mornay and Lobster Thermidor naturally have distinct flavor profiles.

Lobster Mornay tastes predominantly rich, creamy, and cheesy, with notes of nutmeg and cayenne contributing warmth. The béchamel-based sauce is the highlight, with the sweet lobster meat playing a supporting role.

Lobster Thermidor puts more emphasis on the natural flavor of the lobster meat itself, which is sautéed in butter at the start. The rich egg, cream, and brandy sauce complements rather than dominates the lobster. There are robust notes from the cognac or sherry. The overall flavor is elegant, luxurious and complex.

Preparation Methods Are Also Different

To highlight the sauce differences even further, the preparation method for each recipe also varies:

• Lobster Mornay can be made almost entirely on the stovetop in one pan. The béchamel sauce is prepared first before the lobster meat is added directly to the pan and coated in the sauce.

• Lobster Thermidor involves multiple steps across the stovetop and oven. First the lobster meat is sautéed in butter. The sauce is made separately on the stove. Then everything is combined and finished in the hot oven.

So Lobster Thermidor requires a bit more work overall compared to the more straightforward one-pan approach of Lobster Mornay.

Origins and History Are Unique

Finally, Lobster Mornay and Lobster Thermidor have their own interesting backstories and origins:

• Lobster Mornay is named after the French cooking expert Pierre Mornay. Mornay sauce was one of his specialties, which he enhanced by combining it with lobster meat.

• Lobster Thermidor was invented in 1894 by Marie’s, a Parisian restaurant, to commemorate the opening of the play Thermidor. Its creation is credited to chef Marie-Joseph-Félix Landelle.

Knowing the unique histories makes these dishes even more culturally fascinating to me as a food lover.

Putting It All Together

• Sauces – Lobster Mornay features a creamy béchamel base while Lobster Thermidor uses an egg-enriched brandy cream sauce.

• Texture – Mornay develops a browned crust from high heat while Thermidor stays uniformly silky.

• Flavor – Mornay tastes predominantly rich, cheesy and creamy while Thermidor emphasizes the natural lobster flavor.

• Preparation – Mornay is made in one pan on the stovetop while Thermidor uses multiple steps across stove and oven.

• Origins – Mornay is named for French cooking expert Pierre Mornay while Thermidor was created to celebrate a play opening.