- Melt the chocolate and butter in a metal bowl placed over a pot or barely simmering water, stirring gently until melted. Remove from the heat and allow to cool while preparing the other mousse components.
- Whip the cream to soft peaks and stir in the espresso and brandy. Chill until ready to use.
- In a clean bowl, whip the egg whites with the salt until foamy, then gradually add the sugar while continuing to whip the whites until they hold a soft peak when the beaters are lifted.
- By now the chocolate should be cooled to just above room temperature. Fold the whipped cream quickly into the chocolate in 2 additions, then fold in the whites all at once (the mousse will be soft). Pour this into desired serving dishes and chill until set, about 3 hours. Top with chocolate shavings before serving.