Fish Stock Sauce (Second Method)

Ingredients

• 1 décilitre fish fumet (concentrated fish stock)
• 5 egg yolks
• 500 grammes butter

Instructions

1. Reduce the fish fumet (concentrated fish stock) by half over moderate heat.
2. Remove from heat and whisk in the egg yolks. Mount the sauce with butter (monter au beurre), proceeding exactly as you would for a hollandaise sauce (sauce Hollandaise)—adding the butter in small pieces while whisking constantly over very gentle heat until the sauce is pale, thick, and silky.