Make the chocolate cups: In the top of a double boiler combine the chocolate chips and vegetable shortening.
Once the chocolate is melted coat the molds generously. Chill until set and coat again. Chill until ready to serve.
Make the coffee mousse: In a heavy saucepan, combine marshmallows and coffee; cook and stir over low heat until melted. Remove from the heat and cool to room temperature.
Gently fold in whipped cream until well combined. Chill until ready to serve, at least 2 hours.
When ready to serve, gently remove the chocolate cups and place on plates. Spoon coffee mousse into cups but don't overfill them.