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 - Blend raspberries in a food processor or blender until completely smooth. For seedless sorbet, press puree through a fine-mesh sieve into a clean bowl, discarding the seeds.
03 - Whisk lemon juice and cooled simple syrup into raspberry puree. Add lemon zest if using and stir thoroughly to incorporate all ingredients.
04 - Pour mixture into ice cream maker and churn following manufacturer's instructions until mixture reaches thick, slushy consistency, approximately 20–25 minutes. Alternative method without machine: freeze in shallow container for 1 hour, then rake with fork to break crystals. Repeat every 30 minutes for 2–3 hours until smooth.
05 - Transfer churned sorbet to airtight container and freeze for minimum 2 hours to firm completely before serving.
06 - Scoop into chilled bowls or cones. Garnish with fresh raspberries and mint sprigs if desired.