Brew the espresso and let it cool to room temperature. Stir in the coffee liqueur if using and 1 tablespoon of the sugar. Set aside in a shallow dish.

In a mixing bowl, add mascarpone, the remaining sugar, vanilla, and a pinch of salt. Beat on low just until smooth and combined. Do not overmix or it can turn grainy.

In a separate chilled bowl, whip the cold heavy cream to medium-soft peaks. It should hold shape but still look glossy.

Gently fold the whipped cream into the mascarpone mixture in two additions until uniform and silky.

Briefly dip each ladyfinger in the cooled espresso—about 1 second per side. Don’t soak or they’ll fall apart.

Arrange a snug layer of dipped ladyfingers in a small dish (8x8 inches works) or assemble in 4–6 dessert glasses.

Spoon half of the mascarpone cream over the cookies and smooth. Add a second layer of dipped ladyfingers, then the remaining cream.

Cover and chill for at least 3 hours, or up to 24 hours. The flavors meld and the texture sets as it rests.

Before serving, dust generously with cocoa powder and finish with dark chocolate shavings if you like.