Essence of mushroom can be made by placing the trimmings of mushrooms in a saucepan, stewing them gently, and extracting the flavour.

The large black mushrooms, however, are not suited.

In addition to this essence of mushroom, a little lemon juice--allowing the juice of half a lemon to every pint, should be added to the sauce, as well as a slight suspicion of nutmeg, a pint of sauce requiring about a dozen grates of a nutmeg.

A little cream is a great improvement to this sauce, but is not absolutely necessary.

The sauce should be perfectly smooth.