Parisian Sauce

To make the essence, cook two ounces of truffle parings in three gills of boiling dry white wine with some parsley, bay leaf, and a small minced shallot, then leave it for half an hour in a high covered saucepan in a bain-marie before draining it over a sieve. Pour this essence into a pint of veloute (No. 415); reduce and add two spoonfuls of meat or chicken glaze (No. 398), a pinch of cayenne, and stir in just when ready to serve two ounces of butter and the juice of a lemon.