Place the cream and milk in a pan and bring slowly to the boil.
When the liquid starts to creep up the sides of the pan, adjust the heat so that it maintains a medium boil and continue to cook for a good 5 minutes until slightly reduced.
Meanwhile, place the gelatine leaves in a bowl of cold water to soak for 10 minutes until they soften.
Stir the sugar into the reduced cream mixture with the rum and allow to dissolve.
Remove from the heat and leave to cool for a few seconds.
Drain the gelatine leaves and gently squeeze dry.
Add to the pan and whisk continuously until dissolved.
Leave to cool.
Divide the mixture equally between 4 x 120 ml/4 fl oz ramekins or dariole moulds (normally metal moulds with rounded edge at the bottom).
Place on a baking sheet and leave them to set in the fridge for at least 3 hours or up to 2 days is fine.
To serve, dip the dariole moulds into hot water for a few seconds, then gently pull the pudding away from the sides of the mould with a small palette knife.
Invert and gently shake out on to serving plates.
Arrange three of the raspberries on each plate and a dash of cream if desired.