For the mandarine compote: Place the mandarine juice in a saucepan and then mix in the agar.
Bring to the boil and then immeditately pour into a tray to cool.
Once cold and firmly set, place in a liquidizer and blend. Add the xanthane gum if the compote is not thick enough.
Add essential oil to taste.
For the water-based chocolate mousse: Melt the chocolate.
Mix together the water and the first amount of xanthane gum using a hand blender and then warm to 50'C.
Pour two thirds of this mixture on to the melted chocolate. Leave for 20 seconds and then start an emulsification.
Add the rest of the water and mix to obtain an elastic and shiny mixture.
Whip the egg whites and the dextrose together to a meringue mixture. Add the rest of the xanthane gum.
Delicately fold the meringue mixture into the chocolate emulsion and then pour into moulds/cups/glasses. Set aside to set.
Since there is no cream in this recipe, the mousse can be made warm. Make sure to pour into the moulds before the cacao butter starts to set.
To serve: you can either place a little of the mandarine compote in the base of your moulds/glasses and then add the mousse. Alternatively, serve the compote alongside the mousse.