01 - Combine sugar and water in a small saucepan. Heat over medium heat, stirring constantly until sugar completely dissolves. Remove from heat and allow to cool to room temperature.
02 - Process raspberries in blender or food processor until completely smooth. For seedless sorbet, strain puree through fine-mesh sieve into bowl, discarding seeds.
03 - Whisk lemon juice and cooled simple syrup into raspberry puree. Add lemon zest if using, stirring thoroughly to incorporate.
04 - Pour mixture into ice cream maker and churn according to manufacturer instructions until thick and slushy, approximately 20–25 minutes. Alternative method: Pour into shallow freezer-safe container, freeze 1 hour, then rake with fork to break crystals. Repeat every 30 minutes for 2–3 hours until smooth.
05 - Transfer sorbet to covered container and freeze minimum 2 hours before serving. Scoop into bowls or cones, garnish with fresh raspberries and mint if desired.