½ cup cornstarch
½ cup sugar (or more to taste)
Dark chocolate, roughly chopped
Pistachios, roughly chopped
Chop up the watermelon, remove any seeds and toss it into a blender or food processor. Blend until smooth. Place the cornstarch in a medium pot. Add in some of the watermelon juice (about 1 cup) and stir until smooth and the cornstarch has dissolved completely. Add in the rest of the juice and stir. Bring to a slow simmer over medium low heat. Add in the sugar. Cook for about 10 minutes, allowing the mixture to thicken. Continue to stir. When the mixture coats the back of the spoon, remove from heat. Pour into bowls, glasses, ramekins. Place in the refrigerator and chill until set, approximately 4 hours. Sprinkle with the dark chocolate and pistachios. Serve with freshly whipped cream if you desire.