A rich icing/filling made of semisweet chocolate and whipping cream, heated and stirred together until the chocolate has melted. The mixture is cooled until lukewarm and poured over a cake or torte. Ganache soufflé is made from the same base but often includes a tablespoon or so of rum or cognac. When cooled to room temperature, the mixture is whipped to approximately twice its original volume. Whereas ganache is used to glaze cakes, pastries and tortes, ganache soufflé is generally used to fill them.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.