In a small pan, stir together sugar and gelatin.
Stir in water and let stand for 5 minutes or until gelatin has softened.
Stirring constantly, bring to a full rolling boil over high heat.
Remove pan from heat and stir in whipping cream.
In a bowl, stir together sour cream and vanilla; gradually beat into hot gelatin mixture until smooth.
Pour into 8 dessert glasses or into a 4 to 5-cup serving bowl.
Cover and refrigerate for at least 4 hours or until next day.
Accompany each serving with berry sauce or strawberries, if you wish.