Pour the clementine juice into a pan on a high heat to warm through – don’t let it boil. Add a little sugar to sweeten – not too much, you still want that zippy clementine flavour.
Peel the ginger and grate a tiny bit into the pan. Grate a bit more onto a chopping board, then squeeze it over the pan of juice so you get a few drips of ginger juice in there. Take the juice off the heat.
Sprinkle the gelatine over the juice, then whisk in quickly.
Arrange 6 small serving glasses on a tray. Peel the clementines, slice into thin rounds and put 2 in each glass. Sieve the juice mix into each glass, allow to cool, then refrigerate for about 3 hours, or until set.
To serve, mix the vanilla into the yoghurt and dollop a spoonful on top of each jelly, then grate or shave a few pretty bits of chocolate on top.
The amount of gelatine you’ll need will vary depending according to the type, so check packet instructions and adjust accordingly. Buy vanilla syrup at good supermarkets and delis.