Sicilian watermelon jelly studded with chocolate chips and pistachios is a summer jewel. This refreshing mediterranean dessert is a beloved family treat during July and August.
Cut the seedless watermelon into chunks and puree in a blender until completely smooth. Strain the puree through a fine-mesh sieve to remove pulp. Measure out 4 cups of juice.
In a heavy-bottomed saucepan, whisk the cornstarch with granulated sugar. Gradually pour in the watermelon juice while whisking constantly to avoid lumps.
Set the saucepan over medium-low heat. Cook, stirring continuously, until the mixture begins to thicken; then reduce heat to low and continue stirring until it reaches a pudding-like consistency, about 10–15 minutes.
Remove from heat and stir in vanilla extract, rosewater, and lemon zest. Allow the mixture to cool slightly for 2 minutes, then fold in chocolate chips and half of the pistachios gently.
Pour the mixture evenly into individual serving glasses or a medium dish. Cool to room temperature, then refrigerate at least 4 hours until set. Before serving, garnish with remaining pistachios and extra chocolate chips.