• ½ pt. Béchamel sauce
• 1 egg yolk
• ¾ oz. Parmesan cheese
• ¾ oz. Gruyère or Cheddar cheese
• ⅛ pt. cream (optional)
• cayenne pepper

For a Fish Dish

• ¼ pt. fish stock reduced to 2 tablesp. or 2 tablesp. fish fumet

Add the egg yolk mixed with a little cooled sauce to the Béchamel sauce well below boiling-point. Cook the egg yolk without boiling it. Stir in the grated cheese and the cream, season and serve the sauce at once. If fish fumet is used add it hot, before the cream.

Serve with fish or vegetables.