As you will see in this book, chocolate mousse is a favourite of mine to bind ingredients together in the cake. Depending on how you want to use the mousse, it is possible to create a looser or thicker mousse by altering the temperature of the base of the mousse before folding in the cream. Care must be taken with this, as a too-thin mousse mixture will lose volume and texture, while a too-thick mousse mixture will hinder your chances of getting that smooth finish required.
I have written the mousse recipes with this in mind to give you the best chance of a professional-looking cake or dessert, so please adhere to the instructions as closely as possible. Chocolate can be temperamental and is an expensive luxury ingredient, so care must be taken when using it so that a recipe is not spoiled.