Mix 1 1/2 cup espresso (cool) with 1 tbsp Kahlua coffee liquor (optional).
Dip the Savoiardi ladyfinger biscuits quickly in the coffee (be swift - do not soak else they will be soggy) Line them in a 10x10 inch square springform pan, or a similar sized cake pan.
Spoon 1/2 of the tiramisu mousse over the lady finger biscuits. Dust with 1-2 tbsp cocoa powder.
Repeat process with another layer of coffee-dipped lady fingers, a thin layer of tiramisu mousse this time (as we will be piping tiramisu rosettes as the final layer) and again, a thin dusting of cocoa.
Using the remaining tiramisu mousse, pipe rosettes (I used a Wilton 1M tip) as the final layer
Speckle a little cocoa powder (not too much otherwise the beautiful rosettes will not be visible) and sprinkle a bit of edible gold dust for that festive cheer.
Refrigerate 4 hours or overnight and enjoy.