In a shallow dish, combine the cooled brewed coffee with 1 tablespoon of cocoa powder. Dip each ladyfinger briefly into the coffee mixture, ensuring they are soaked but not soggy. Set aside.
In a mixing bowl, combine the mascarpone cheese, heavy cream, powdered sugar, and vanilla extract. Use an electric mixer to whip the mixture until it forms soft peaks. This will create a fluffy and creamy filling.
Take a trifle dish or individual serving glasses and start layering. Begin with a layer of dipped ladyfingers at the bottom of the dish.
Spoon a layer of the mascarpone cream over the ladyfingers, spreading it evenly.
Repeat the process, creating additional layers of ladyfingers and mascarpone cream until the dish is filled, finishing with a layer of mascarpone cream on top.
Cover the trifle dish with plastic wrap and refrigerate for at least 4 hours, preferably overnight to let the flavors meld together.
Before serving, garnish the top of the trifle with dark chocolate shavings and a dusting of unsweetened cocoa powder for an elegant finish.
Notes
For best results, refrigerate overnight to enhance the flavors.