Steps
1. Brew espresso and let it cool; mix with coffee liqueur if using.
2. In a bowl, whisk mascarpone, powdered sugar, heavy cream, and vanilla extract until smooth and slightly thickened.
3. Quickly dip ladyfingers into the espresso mixture, ensuring they are soaked but not soggy.
4. Arrange soaked ladyfingers in a small serving dish or glass.
5. Spread half of the mascarpone mixture over the ladyfingers.
6. Repeat with another layer of dipped ladyfingers and the remaining mascarpone cream.
7. Dust the top generously with cocoa powder.
8. Refrigerate for at least 2 hours before serving for best flavor and texture.