Brew espresso: Brew 1 cup of strong rich espresso or robust dark coffee. Stir in 1 tablespoon of brown sugar until fully dissolved. Allow to cool completely to room temperature in a shallow bowl.

Whip heavy cream: In a chilled metal or glass mixing bowl, beat the cold heavy whipping cream with an electric hand mixer on medium-high speed until stiff peaks form (about 3-4 minutes). Set aside.

Beat mascarpone: In a separate large bowl, beat the chilled mascarpone cheese, powdered sugar, and pure vanilla extract on medium speed for 1-2 minutes until smooth, glossy, and lump-free.

Fold the cream: Gently fold the whipped cream into the sweetened mascarpone mixture in three additions using a rubber spatula, lifting from the bottom in slow motions until a cloud-like, silky cream forms. Transfer cream into a large pastry piping bag fitted with a wide round tip (or use a spoon).

Dip ladyfingers: Break savoiardi ladyfingers in half or thirds to fit into the bottoms of 4 to 6 clear glass dessert tumblers or jars. Quickly dip each biscuit piece into the cooled espresso for just 1-2 seconds per side (do not soak, or they will turn soggy).

Assemble layers: Place a layer of espresso-dipped ladyfingers into the bottom of each glass cup. Pipe a generous, billowy layer of mascarpone cream over the biscuits. Repeat with a second layer of dipped ladyfingers, and finish with a top decorative layer of piped mascarpone cream.

Chill to set: Cover the dessert cups loosely with plastic wrap and refrigerate for at least 4 hours (ideally overnight). The chill time softens the biscuits into delicate cake and allows the espresso and vanilla flavors to marry beautifully.

Dust & serve: Right before serving, place Dutch-process cocoa powder in a fine-mesh sieve and dust generously across the tops of each cup. Garnish with shaved dark chocolate curls and a fresh mint leaf. Serve chilled with small dessert spoons!