Combine sugar, Pedro Ximénez and 2 cups water in a saucepan and bring to the boil over medium heat, add chocolate and stir until smooth. Squeeze excess water from gelatine, add to chocolate mixture and stir to dissolve. Divide among six 1-cup capacity serving glasses and refrigerate for 3-4 hours or until set.
For white chocolate crème fraîche, combine white chocolate and crème fraîche in a heatproof bowl and place over simmering water, stirring occasionally until melted and smooth. Remove from heat, add cream, mix and refrigerate until cold. Whisk until soft peaks form, spoon over jelly and serve.