01 - Combine water and sugar in a small saucepan. Bring to a gentle boil over medium heat, stirring constantly until the sugar completely dissolves, approximately 2–3 minutes.
02 - Remove the saucepan from heat and add fresh mint leaves. Allow the mixture to steep for 10 minutes to extract the mint flavor into the syrup.
03 - Strain out the mint leaves using a fine mesh strainer. Let the mint-infused syrup cool completely to room temperature.
04 - In a mixing bowl, whisk together the cooled mint syrup, freshly squeezed lemon juice, and grated lemon zest until fully incorporated.
05 - Pour the mixture into an ice cream maker and churn according to the manufacturer's instructions for 20–25 minutes until the texture becomes thick and slushy.
06 - Transfer the churned sorbet to a freezer-safe container, cover tightly, and freeze for at least 4 hours or until firm enough to scoop.
07 - Scoop the sorbet into chilled bowls or glasses. Garnish with fresh lemon slices and mint sprigs if desired. Serve immediately.