Whip mascarpone cheese and powdered sugar in a bowl until smooth.
In another bowl, whip heavy cream until soft peaks form.
Gently fold the whipped cream into the mascarpone mixture.
Brew espresso and let it cool, then stir in the coffee liqueur (if using).
Dip each ladyfinger quickly into the espresso, making sure they’re soaked but not soggy.
Layer the soaked ladyfingers in your dish or cups.
Spread a generous layer of whipped mascarpone mixture over the ladyfingers.
Repeat with another layer of soaked ladyfingers and mascarpone.
Smooth the top and refrigerate for at least 3 hours.
Before serving, dust with cocoa powder.