In a large saucepan, combine the milk, rum, syrups and brown sugar. Cook over medium heat until hot (do not boil). Stir in coffee and liqueur., Meanwhile, in a small bowl, beat cream until it begins to thicken. Add confectioners' sugar; beat until stiff peaks form. Fold in liqueur until combined., Pour coffee mixture into mugs. Garnish with a dollop of coffee whipped cream and, if desired, espresso powder.