For the vanilla panna cotta, put the cream and sugar into a saucepan.
Split the vanilla pods, using a sharp knife scrape the seeds into the cream, and add the pods. Bring to the boil.
Squeeze any excess water from the soaked gelatin. Add it to the hot cream and whisk to dissolve. Pour the mixture into six individual dariole moulds.
Place into the fridge and leave to set.
For the ‘roasted’ watermelon, fry the watermelon in a pan until coloured all over.
For the soup, blend all the excess watermelon in a blender or food processor.
In a pan, heat the sugar and 100ml/3½fl oz water until the sugar dissolves. Leave to cool down. Stir in the mint, ground ginger and blended watermelon and put in the fridge to chill.
Once the panna cotta has set, turn each one out onto a plate.
Serve with the chilled soup and caramelised watermelon chunks.