Place watermelon chunks in a blender or food processor and puree. Strain through a sieve. Place about two-thirds of the watermelon juice in a medium pot and turn the heat on low.
In a separate bowl, whisk the remaining one-third of the watermelon juice with the corn-starch, sugar, cinnamon, and cloves until a smooth slurry.
When you see little bubbles forming on the perimeter of