Combine sugar and water in a small pan and boil 3 minutes. In a food processor with metal blade, process the cream uninterrupted until firm peaks form, only about 50-60 seconds. Transfer to a large bowl. Reinsert blade and add chocolate. Process turning on and off for 15-20 seconds. Continue processing and gradually add hot syrup, Triple Sec, and yolks until just combined. Pour over whipped cream and fold together.

Finished mousse can be poured into individual cups, ramekins, or into a 7 inch bowl. Immediately cover and refrigerate. Remove just before serving. Any leftovers should be refrigerated right away.