Sauce Nantua
Béchamel enriched with crayfish butter and cream
The luxurious one: béchamel finished with a butter pounded from crayfish shells. Traditionally served with quenelles de brochet, and it is what makes that dish worth the trouble.
Shrimp or lobster shells stand in perfectly well for crayfish.
Ingredients
Crayfish Butter
- 8 ounces crayfish, shrimp or lobster shells
- 8 tablespoons unsalted butter, softened
Sauce
- 3 cups Béchamel, hot (see Béchamel)
- 1/2 cup heavy cream
- 2 tablespoons Cognac
- A pinch of cayenne
- Kosher salt and white pepper
Instructions
Crayfish Butter
- Dry the shells in a low oven (300°F) for 15 minutes, then pound them in a mortar or blitz in a food processor with the softened butter until you have a coarse pink paste.
- Melt the paste gently in a small pan over low heat for 10 minutes, then strain through a fine sieve lined with muslin, pressing hard. Chill until firm.
Sauce
- Bring the béchamel to a bare simmer, stir in the cream, and reduce for 5 minutes.
- Off the heat, whisk in the crayfish butter a piece at a time until glossy.
- Add the Cognac, cayenne, salt and white pepper. Do not boil once the butter is in.
Notes
- The crayfish butter keeps a month in the freezer. Make it whenever you cook shellfish and have shells to spare.
- Straining through muslin is what keeps grit out. Do not skip it.