In a large, heatproof bowl, whisk together the wine, Irish cream liqueur and sugar. Then whisk in the egg yolks. Set the bowl over a pan of gently boiling water (the bottom of the bowl shouldn’t touch the water) and whisk constantly until the Sabayon is thick and has doubled in volume, about 5 minutes. Then immediately set the bowl in an ice water bath and let cool, stirring occasionally, about 10 minutes.
Combine all of the syrup ingredients in a small mixing bowl and set aside.
In a large mixing bowl, either using an electric hand mixer or a stand mixer beat together all of the mascarpone cream ingredients (except powdered sugar) at a medium-high speed until the mixture is smooth and thick. Stir in the powdered sugar.
NOTE: The cream can be made 1 day ahead of time and held in the refrigerator until the dessert is ready to be assembled.
Fold the Sabayon mixture into the mascarpone cream mixture until blended.
Use an 11 x 7 x 2 inches pan or adjustable cake mousse mold.
Dip ladyfingers on both sides quickly into syrup and arrange them into the pan or mold until you have used half the cookies and then evenly spread over half of the creamy mixture.
Using the coarse side of a grater, grate the chocolate over the cream. Repeat with another layer of soaked ladyfingers and then top with the remaining mascarpone mixture.
If you want a pretty finish, you can pipe on the final cream layer. Cover the dish with cling film wrap and leave in the fridge overnight.
Dust on top with cocoa just before serving.
