For the nut-rice flummery, cut the vanilla pod lengthwise.
Cook the rice with the sugar, vanilla pod, cinnamon and salt in the milk over a low heat, cover and leave to cool, remove the vanilla pod.Mix the nuts with the rum.Soak the gelatine in cold water for 5 minutes, squeeze out well and dissolve in a little hot water.Whip the Cremefine and fold into the rice with the gelatine and the nuts. Rinse the ramekins in cold water. Pour in nut-rice mixture and refrigerate for 2 hours.
For the chocolate sauce, chop chocolate.Set aside 3 tablespoons of the Cremefine, bring the rest to a boil. Add the chocolate and stir to dissolve. Season with Cointreau and let cool.Beat 3 tablespoons of Cremefine until creamy and arrange with the chocolate sauce on precooled dessert plates.
Turn the nut-rice flummery out of the ramekins onto the plates and garnish with half walnuts.