01 - Line an 8x8 inch baking pan with parchment paper and lightly grease the surface.
02 - In a small saucepan, mix watermelon puree, corn syrup, and lemon juice until fully combined.
03 - Sprinkle unflavored gelatin powder evenly over the mixture and allow it to hydrate for 5 minutes.
04 - Stir in granulated sugar. Warm the mixture over medium-low heat, stirring constantly until the gelatin and sugar are fully dissolved without bringing to a boil.
05 - Pour the hot mixture into the prepared pan. Smooth the surface and let it cool at room temperature for 30 minutes.
06 - Refrigerate uncovered for 2 hours or until the mixture is completely set.
07 - In a bowl, mix granulated sugar with citric acid until evenly combined.
08 - Using a sharp knife, cut the set mixture into small squares. Roll each piece in the sour sugar mixture to ensure an even coating.
09 - Place chews in an airtight container, separating layers with wax paper to prevent sticking.