In a mixing bowl, combine the mascarpone cheese and icing sugar. Mix until smooth.
In a separate bowl, whip the double cream until stiff peaks form.
Gently fold the whipped cream into the mascarpone mixture until well combined.
Stir in the vanilla extract.
In a shallow dish, mix the cooled coffee with the coffee liqueur (if using).
Quickly dip each ladyfinger biscuit into the coffee mixture, ensuring they are soaked but not soggy.
Arrange a layer of soaked biscuits in the bottom of a serving dish.
Spread half of the mascarpone mixture over the biscuits.
Repeat with another layer of soaked biscuits followed by the remaining mascarpone mixture.
Spread or pipe the remaining mascarpone cream on top.
Cover and refrigerate for at least 2 hours to set.
Before serving, dust the top with cocoa powder.
