Chop the Caramilk chocolate into small pieces, and place in a medium-sized heatproof bowl.
Heat half the cream in a small saucepan, over medium-high heat until bubbles begin to form around the edges.
Pour the cream over the chopped Caramilk, and leave for a few minutes to melt. Whisk until all of the chocolate is melted and the mixture is smooth and well combined.Stir in the remaining half of the cream (adding cold cream helps cool the mixture down faster).
Taste the mixture, and if the mixture is too sweet, whisk in a pinch of salt to counter the sweetness, if you wish.
Cover the bowl with plastic wrap and chill the mixture until it is very cold. This can be done either in the fridge or freezer.Fridge - refrigerate for at least several hours or overnight.Freezer - place in the freezer for 1 hour, stirring every 10 minutes to make sure it doesn't freeze around the edges.Chilling overnight in the fridge is the best option, but I know sometimes we just want mousse in a hurry, so the other options are there if you need them.
Whip the mixture with an electric hand mixer just until stiff peaks start to form. It won’t take very long, so keep a close eye on it and be careful not to over-whip, or it will become grainy.
Pipe or spoon the mousse into glasses or small bowls. If it’s a little too soft to pipe, you can refrigerate the bowl of mousse again until it firms up some more, and then transfer it to a piping bag to pipe.
Serve the mousse immediately for a softer mousse, or pop them in the fridge for an hour or two to set, for a fluffier mousse. Serve topped with an extra square of Caramilk, if you like.
The mousse can be stored in the fridge for several days. Cover each glass with plastic wrap, or put all of the glasses into a lidded container.The unwhipped mousse mixture will keep well, covered, in the fridge for 1-2 days before whipping.
Notes
Cream - The cream you need for this recipe is known by different names in different countries. Here in NZ, it’s usually called standard cream or whipping cream, in other countries, it may be known as full cream, heavy cream or heavy whipping cream. Double cream is generally too thick for this recipe it contains a lot more fat (although the fat content can vary by country.) Long story short: for best results, choose a pourable cream that is around 35% fat. Make sure that it says on the bottle/carton that it is suitable for whipping.