Cut ladyfingers into three pieces if using tall thin glasses. Place a layer of cookies on the bottom of each glass. The bottom layer should come 1/4 of the way up the glass, or a bit less.
In a small bowl combine the prepared coffee, brown sugar, vanilla and rum extract. Mix well, then pour evenly over each parfait.
In a medium bowl combine the mascarpone, whipped cream, sugar, and coffee. Use a hand mixer and whip until smooth. Spoon into glasses so the mixture comes 3/4 of the way up the glass. Leave the top 1/4 of each glass for the whipped cream portion.
Top each parfait with whipped cream. Dust the top with cocoa powder. Hold a sieve over the first glass and then add 1 teaspoon of cocoa powder inside and start to shake it so it lightly dusts the top of each parfait. You can use more, or less, according to taste.
Grate chocolate over top of each glass.
Place the parfaits in the fridge and chill for about 1 hour.
Serve with a big old Dunkin’ Donuts® Coffee loving smile!