In the bowl of your electric mixer, whip the heavy cream with the icing sugar, the vanilla, and the salt until stiff peaks form. Mix about 1 cup of the whipped cream with the white chocolate mixture to lighten it up and then add half of this mixture to thewhipped cream and fold gently using a spatula. Add the remaining white chocolate mixture and fold again until combined. Refrigerate for at least 4 hours or until completely set.
You can make the cake one day in advance since it needs some time in the refrigerator to set properly.
You can use a 10-inch (25 cm) springform pan and make two layers of cake and two layers of mousse. The cake will be wider and shorter, but easier to make and just as delicious!
This cake should be stored in the fridge.
Preparation time doesn't include refrigeration time.