Preheat the oven to 180 degrees Celsius.
Zest the orange and the lemon. Squeeze the juice from the orange. Wash the rhubarb and cut into pieces about 5cm long and half a cm wide. Place on a baking tray and sprinkle the caster sugar over them. Place in the oven and bake for about 10 minutes. Remove from the oven and leave to cool.
Neatly cut the cantaloupe melon in half and remove the seeds. Use a melon baller or a teaspoon to scoop small balls out of the flesh. Scoop small balls from the watermelon flesh too, getting rid of any seeds. Cut the watermelon balls into small pieces.
Mix the orange juice, the citrus zest, the verbena and the caster sugar in a pan and bring to the boil. Bring to the boil and then reduce to a syrup. Place the chopped watermelon in a food processor, add the syrup and blitz to make a 'soup'.
Scrape out the two halves of the cantaloupe melon shell and then fill with the melon balls. Pour the 'soup' over the melon balls and finish with the rhubarb sticks.
Serve ice cold.
«Serve the salad in the melon shell and then spoon individual helpings into glasses or verrines»