Combine the ginger, 100 grams white sugar and 60 ml water in the thermomix. Heat at 100c for 5 minutes on speed 3. Remove from heat, strain the ginger and allow to stand until cool.
Combine the watermelon and the sugar in the thermomix and process on speed 8 for 10 seconds. Pour the ginger syrup on to the watermelon. Pour into ice cube trays and freeze.
When the watermelon cubes are frozen, process once more on the thermomix on speed 10 for around 20 seconds. Use the spatula to assist in the mixing of the sorbet. Top with the finely diced watermelon. Hint: If you want, use a fork to scrape on the sorbet until you get the granita like texture.