• ½ pt. sauce made with meat or fish stock, milk or milk and stock
• 1 teasp. dry English mustard or 1 tablesp. French mustard
• 1 teasp. tarragon vinegar
• 1 teasp. sugar
• ½–1 oz. butter

Mix the dry mustard with the vinegar. Whisk the mixed mustard and sugar into the hot sauce. Whisk the butter into the sauce just below boiling-point, adding it a small pat at a time.

Serve with boiled beef, herring or mackerel