Stir the chocolate in a large metal bowl set over a saucepan of simmering water until the chocolate melts. Allow the chocolate to cool slightly. Using an electric mixer, beat 1 cup of cream in another large bowl until it is thick and fluffy. Fold 1/4 of the whipped cream into the chocolate. Fold half of the remaining whipped cream into the chocolate mixture. Fold in the remaining whipped cream. Spread the chocolate cream over the cake, covering completely and creating a well in the center. Cover and refrigerate if not assembling cake right away.
In another clean large bowl, add the remaining 1 cup of cream and almond extract. Using an electric mixer with clean beaters, beat on medium speed and gradually add the powdered sugar. Beat until firm peaks form. Fold in the nuts. Spoon the cream mixture into the center of the well of the filling.
Brush the remaining cake slices with brandy and arrange them, brandy side down, over the cake, covering the filling completely and trimming to fit, if necessary. Cover the cake with plastic wrap and refrigerate at least 3 hours and up to 1 day.