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Classic Mermaid Thermidor

The dish that ruined lobster for an entire generation of yacht-club members.

By The Galley · Updated 2026-10-16

Cartoon of a golden, cheese-topped mermaid tail on a long silver platter
Prep
1 hr
Cook
2 hr
Total
3 hr
Serves
8 (one very long platter)
Difficulty
Legendary
Cuisine
Old-world Nautical
Course
Main

The story

I first made this Thermidor for a dinner party in 1987. Three guests fainted and one became a vegetarian. I took it as a compliment.

It is rich, it is golden, and it takes longer to make than most sea voyages. That is the point. Good things come to those who wait, and mermaids come to those who wait near rocks at dusk.

Ingredients

For the tail

  • 1 mythical mermaid tail, sustainably imagined, scales kept for serving
  • 2 tbsp butter

For the sauce

  • 2 cups cream
  • ½ cup brandy, for the sauce, and for the chef's nerves
  • 1 tbsp Dijon mustard
  • 2 egg yolks

To finish

  • 1 cup grated Gruyère
  • paprika, for that sunset-over-the-rocks look

Equipment

  • Platter roughly the length of a rowboat
  • Heavy saucepan
  • Broiler
  • Earplugs

Method

Before you begin

  1. Confirm your mermaid is fresh. She should still be singing.
  2. Insert earplugs and set your face to "neutral". She will try to make conversation.

Make the sauce

  1. Warm the cream in a heavy saucepan. Whisk in the mustard and yolks off the heat. ⏱ 10 min
  2. Add the brandy. Take a moment for yourself.

Cook the tail

  1. Simmer the tail meat gently in the sauce until the singing stops and the kitchen goes uncomfortably quiet. ⏱ 1 hr 30 min
  2. Spoon everything back into the scales, top with cheese and paprika, and broil until golden. ⏱ 8 min

Serve

  1. Present on a platter large enough to make your guests reconsider their life choices.

Substitutions

  • No mermaid? Lobster works, but your guests will know.
  • No brandy? Use the captain's rum. Do not tell the captain.

Storage and leftovers

Keeps 2 days in the fridge. Cover tightly, or it will hum quietly to the leftovers.

Nutrition (per serving, allegedly)

Calorieslegendary
Proteinmythical
Regret0 g (we checked)

Tags: Classic Dinner Party Make Ahead