Open phyllo shells, leaving shells in tray; set aside.
In a small saucepan melt the 1-1/2 cups dark chocolate and whipping cream over low heat, stirring occasionally. Divide melted chocolate mixture evenly among the bottoms of the phyllo shells; set aside.
In a medium mixing bowl, stir together brown sugar, coffee liqueur, espresso powder, and vanilla; stir until espresso powder dissolves. Add cream cheese and stir until well combined. Spoon a small amount of cream cheese mixture over chocolate mixture in each shell. (Or, place cream cheese mixture in a resealable plastic bag, cut off a small piece of one corner, and pipe cheese mixture onto chocolate filling.) Cover tartlets loosely and chill until set (about 30 minutes). Once set, tartlets can be covered tightly and chilled overnight.
Remove tartlets 30 minutes before serving. Sprinkle each lightly with a little cocoa powder. If desired, top each with chopped coffee beans or chopped chocolate.