Soak the 3 gelatine leaves in a little cold water. Place cream, milk, sugar and vanilla sugar into a pan and bring to the boil, simmer for about 5 minutes. Remove the pan from the heat. Squeeze water out of the gelatine leaves and add to the pan, stir until the gelatine has dissolved. Allow to cool for about 30 minutes. Divide the mixture into four glass bowls (each about 225 ml); allow to cool for at least 4
hours. Pour XUXU over the panna cotta, place in the fridge for another 2 hours until set.