Finely grate the peel of 1 lemon. Squeeze the juice of 2 lemons. Mix the sugar and cream cheese together. Stir in the lemon zest, lemon juice and yogurt.
Dissolve the gelatine according to the package instructions, stir into the yoghurt mixture. Pour the mixture into four glass bowls and refrigerate for 2 hours.
Slice the rest of the lemon and then I cut corners and garnish the mousse with it.