Place gelatine in a bowl with water and ice to soften. Pour the whipping cream in a saucepan and add sugar. Cut the vanilla pod lengthwise and scrape pulp out, add whole pod and pulp to whipped cream and bring it to the boil. Once reached boiling point, remove from heat, cover and let rest for 10 minutes.
Remove the vanilla pods, squeeze gelatine and add to the liquid, whisk it until the gelatine has dissolved. Pour liquid into serving bowls or glasses. Put in the fridge for at least 3 hours to set. To serve, sprinkle the panna cotta with sugar and flambé with a blow torch. Finally, pour a dash of rum on the caramelised sugar.