Sauce Diane is simply a sauce poivrade that is folded with whipped cream just before serving. It has a light, airy texture along with incredible depth of flavor. Classic authors call for truffle slices cut into crescent shapes (use a small cookie cutter) and cubes of hard-boiled egg white to be added at the end. The sauce is improved by eliminating the egg white. It is not essential to finish the sauce with truffles, though when used they will add a whole new dimension to the sauce. Cutting them into crescent shapes is a nineteenth-century affectation, and their flavor will certainly not suffer if they are julienned, sliced, or chopped. It is also possible to impart the flavor of truffles by whisking Truffle Butter into the sauce before folding in the whipped cream, or by storing the sliced truffles overnight in the refrigerator in the cream to be whipped.
Make sure that the sauce poivrade is well reduced and quite thick before folding it with the whipped cream. Otherwise, the mixture will separate into a layer of runny sauce covered with a layer of whipped cream. Do not try to serve this sauce too hot, or the whipped cream will fall and the sauce will turn runny.
Keep in mind that truffle juice can be enclosed in spheres (see Spherification), which can be used to garnish the sauce.
Copyright © 2017 by James Peterson. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.