To make the citrus fruit nectar:
Pour all the juices into a saucepan together with the sugar. Cook for about 10 minutes over a medium heat to thicken.
To make the mousse:
Start by grating the zest of the lemons. Put by. Next squeeze the lemons and mix the juice with the condensed milk and the cheese spread to make a smooth, creamy mixture. Add the lemon zest.
Spoon the mousse into the bottom of a dessert glass and pour the citric nectar on top.