In a mixing bowl, whisk the espresso, water and Grand Marnier together, set aside.
In a mixing bowl, combine the Mascarpone and Marsala together and beat until smooth.
In a medium bowl beat the eggs, yolks, and 3 tablespoons of the sugar together until smooth, set over a hot water bath and beat for 3 minutes until light and foamy.
Remove from the heat, and without waiting beat this mixture into the Mascarpone mixture. Set aside.
In two small additions, fold about 1/3 of the Mascarpone mixture into 2 cups whipped cream.
Then fold the whipped cream into the remaining Mascarpone mixture. Set side.
In a standing electric mixer, beat the egg whites and salt on medium speed until foamy.
Increase the speed and add the remaining 3 tablespoons sugar, beat until glossy, not dry.
Fold the egg whites, all at once into the Mascarpone mixture.
Cut the sponge cake into thirds crosswise. Place one layer of the sponge cake in a large loaf pan or a pan the size of the piece of sponge cake. Moisten the cake with a third of the espresso mixture.
Top with a third of the Mascarpone mixture, spreading it out evenly.
Sprinkle generously with cocoa powder, and powdered sugar. Top with the other half of the sponge cake layer. Moisten with the a third of the espresso mixture. Top with a third Mascarpone mixture, spreading evenly. sprinkle generously with the cocoa powder, and powdered sugar.
Top the Mascarpone mixture with the remaining sponge cake. Moisten the cake with the remaining espresso mixture.
Spread the cake with the remaining Mascarpone mixture.
Top the cake with the remaining whipped cream. Garnish the cake with espresso powder and espresso beans Refrigerate the cake, uncovered for 2 hours