Put two spoonfuls of common vinegar into a stewpan, place it over the
fire, and when boiling add eighteen spoonfuls of demi-glace (No. 9), and
six of consommé (No. 134), add a quarter of a teaspoonful of powdered
sugar, place it over the fire and let it reduce very fast until it
adheres lightly to the back of the spoon, then add thirty fresh leaves
of tarragon, let it just boil up and it is ready for use. Do not make it
too long before you require to use it, or the tarragon would spoil the
appearance of the sauce.