For the sorbet, quarter, seed and peel the melon 3 hours before. Cut the flesh into small pieces and puree with icing sugar in a wide bowl. Place in the freezer for at least 3 hours, stirring with a fork about every 30 minutes.
For the rice pudding, bring the milk to the boil in a saucepan. Stir in vanilla sugar and rice, cover and simmer over low heat for about 35 minutes. Stir from time to time. Wed
Whip the cream until stiff and stir into the rice pudding. Divide into six glasses. Cut out balls from the sorbet and arrange on the rice, serve immediately.