Cut off the bottom of the Lady Fingers and line the sides of a 9 inch springform pan. Use the extra end pieces to press into the areas not covered. Set aside.
Fill the bottom part of a double boiler with hot water but not touching the bottom of the top pan. Place the semi-sweet chocolate into the top part of the double boiler pan. Place over a medium heat, stirring until the the chocolate is just melted. Remove from heat and transfer the melted chocolate into the small bowl of an electric mixer. Set aside and allow to cool down to room temperature, stirring occasionally
In a separate bowl dissolve the instant coffee with the 1/2 cup boiling water. Set aside.
On the lowest speed of your mixer, slowly beat in the prepared coffee into the cooled chocolate. Add the vanilla extract and egg yolks. Using a rubber spatula scrape the sides and mixture to keep it smooth. Set aside.
In the large bowl of an electric mixer beat the egg whites and salt at a high speed until soft peaks form. Slowly beat in the sugar until the egg whites are still but not dry. DO NOT beat the egg whites until ready to fold into the chocolate mixture or over beat as the air will fall.
Very gently, lightly fold one (1) heaping teaspoon of the beaten egg whites into the chocolate mixture. Repeat in small batches until half of the egg whites have been folded into the chocolate. Be careful as to not mix vigorously or the egg whites will break. Now, reverse the process and fold the remaining chocolate mixture into the other half of the remaining egg whites, gently folding until no egg whites can be seen.
In a chilled bowl with chilled beaters, at a high speed whip the heavy cream until it holds a soft shape. Gently fold the whipped cream into the chocolate mixture.
Pour the prepared chocolate filling into the Lady Finger Lined springform pan. Cover the top with plastic wrap. Place into the refrigerator for a minimum of five (5) hours. If you wish to prepare a day in advance, leave in the refrigerator overnight.
When ready to serve prepare the whipped cream topping. Whip the heavy cream and sugar at a high speed until soft peaks form.
To Serve: remove from the refrigerator and release the sides of the springform pan. Place a large dessert or cake plate over the ice box cake. Slowly and carefully invert (flip) the cake onto the dessert/ cake plate. A flat metal spatula may be used to gently dislodge the bottom of the pan from the cake.
Spread the whipped cream on top. Sprinkle with chocolate shavings. NOTE: The filling may be place into individual ramekins without Lady Fingers and refrigerated to be served as a pudding.