Cook the sugar at 121°C or 250°F...
...and pour on the eggs while beating with a hand mixer on low speed.
As soon as the sugar has been combined, beat at high speed until fully cooled.
This is called "bomb mix".
Meanwhile melt the chocolate in a bain Marie or in the microwave oven.
Whip up the .
Combine the melted chocolate...
...with the bomb mix.
Gradually add the whipped cream.
The chocolate mousse is ready for use. You can use it for many differents kinds of desserts (chocolate cakes, etc...)