Brew espresso, stir in the cocoa powder and brandy, set aside to cool.
Place the egg yolks and sugar in a large metal mixing bowl, and set it over a pot of simmering water. Cook, whisking, until the mixture, is pale, thick, and doubled in volume (about 5 minutes). Remove from the heat, and whisk in the mascarpone, melted chocolate, vanilla, and salt. Be careful not to whisk too much. Mascarpone is known to break easily.
Whip the 1/2 cup of heavy cream until it holds stiff peaks. Fold the whipped cream into the chocolate mixture. Set the filling aside.
One at a time, dip the ladyfingers into the cocoa mixture and place in an 8x8 pan (my pan was a 9x7). Line the ladyfingers up to fill the bottom of the pan.
Spread half the filling over the ladyfingers, and repeat. Spread the remaining filling on top.
Whipped Topping:
Whip the heavy cream, powdered sugar, cocoa powder, and vanilla until stiff peaks form. Spread evenly over the top, garnish with chocolate shavings if desired.
Refrigerate for at least 4 hours, preferably overnight.