Normande Sauce

Ingredients

• 3 quarts Velouté de poisson (fish velouté — a mother sauce of fish stock, roux, and cream)
• 1 decilitre mushroom cooking liquid (cuisson de champignons)
• 1 decilitre oyster cooking liquid (cuisson d'huîtres)
• 2 decilitres sole fumet (concentrated fish stock)
• a few drops lemon juice (jus de citron)
• 5 whole egg yolks
• 2 decilitres cream (crème)
• 4 decilitres double cream (crème double)
• 195 grams butter (beurre)

Instructions

1. Begin with 3 quarts of fish velouté (a mother sauce). Add to it 1 decilitre each of mushroom cooking liquid and oyster cooking liquid, plus 2 decilitres of sole fumet (concentrated fish stock). Season with a few drops of lemon juice.
2. Prepare a liaison: whisk 5 egg yolks with 2 decilitres of cream until smooth. Slowly temper this mixture into the warm sauce, whisking constantly to prevent curdling.
3. Reduce the sauce over high heat by a full third, bringing it to approximately 8 decilitres total volume.
4. Pass the sauce through fine strainer (étamine) to ensure smoothness.
5. Finish the sauce by mounting with butter (monter au beurre): whisk in 4 decilitres of double cream and 195 grams of butter, stirring gently until fully incorporated and silky. Taste and adjust seasoning as needed.