In a large bowl with a hand mixer or using the whisk attachment on a stand mixer beat together the sugar and the egg (if using) until frothy, then add the mascarpone, Baileys and cream, beat until thickened.
If you leave out the egg then beat together the mascarpone, Baileys, cream and powdered sugar until thickened.
In a medium bowl mix the coffee and Baileys together.
In the baking dish approximately 8x6 inches (20x15cm) place a coffee/Baileys dipped ladyfinger on the bottom, do not let the ladyfingers sit in the coffee mixture, just dip and turn once. Top with 1/3 – 1/2 of the mascarpone mixture and continue for another one-two layers, finish with the remaining mascarpone mixture.
Cover the dish with plastic wrap and refrigerate for at least 3-4 hours or even better overnight. Just before serving sprinkle with unsweetened cocoa powder or chopped or grated chocolate.
Notes
If you like to fancy it up, the last layer on top of the dessert you can use a piping bag with a medium/large hole tip to add the cream mixture. I actually used the back of a spoon to fancy it up a bit.I made two layers, my layer of filling was quite thick so I actually could have and probably should have gone with three layers. Although it was still really good with just the two layers.The Italian dessert should be kept in the fridge in an airtight container or well covered with plastic wrap, it will keep for 2-3 days in the fridge.If you prefer you can freeze it in a freezer safe container, it will keep for up to two weeks in the freezer. Let it thaw overnight in fridge before serving.