1. Sprinkle the gelatin over the water in a small bowl and allow the gelatin to soften. Heat the light cream in a small saucepan and add the gelatin mixture. Stir over medium heat until the gelatin dissolves. Stir in the sugar and remove from the heat.

2. In the container of a blender or processor, combine the avocados, rum, and lemon juice. Whirl until smooth. Blend in the gelatin mixture, then transfer to a large mixing bowl. Cover the bowl and refrigerate for 6 hours or until the mixture is lightly set.

3. Whip the heavy cream in a small bowl, adding the nutmeg just before soft peaks form. Fold into the avocado mixture and spoon into stemmed goblets. Top with additional whipped cream and freshly grated nutmeg.