1. Sift the brown sugar into a bowl. Add the crushed Graham crackers, melted butter, and brown sugar; mix with your fingers.2. In a large bowl, whisk together the mascarpone, sugar, cream, and instant espresso coffee until the mixture is smooth and thick.3. Line the bottom of small rectangular individual cake molds with half of the biscuit mixture.4. Fill with the mascarpone mixture. Cover with the remaining biscuits and refrigerate for 4 hours before serving.5. Unmold and serve immediately.