• ½ pt. white sauce made with milk or fish stock
• 1 rounded tablesp. very finely-chopped parsley
• juice of ½ lemon
• 1 oz. butter

Add the lemon juice and chopped parsley to the hot sauce. Whisk the extra butter into the sauce just below boiling-point, adding it a small pat at a time.

Serve mainly with fish or with poultry.