01 - Combine sugar, 1 cup water, and mint leaves in a small saucepan. Bring to a simmer over medium heat, stirring continuously until sugar completely dissolves. Remove from heat and let steep for 10 minutes to extract mint flavor.
02 - Pour the mint syrup through a fine mesh strainer into a large bowl, firmly pressing on the leaves to extract all flavorful liquid. Discard the spent mint solids.
03 - Add the remaining 1 cup cold water, lemon juice, cranberry juice, lemon zest, and sea salt to the strained mint syrup. Whisk thoroughly until all ingredients are fully incorporated and salt is dissolved.
04 - Transfer the mixture to a shallow metal pan or freezer-safe container. Place in freezer for 1 hour to begin the freezing process.
05 - After 1 hour, remove from freezer and use a fork to scrape the frozen edges toward the center, breaking up ice crystals. Return immediately to freezer.
06 - Continue scraping the mixture every 30-45 minutes for 3-4 hours total. The sorbet is ready when it achieves a light, fluffy, and granular consistency throughout.
07 - Scoop the finished sorbet into chilled bowls or cups. Garnish generously with fresh mint leaves and lemon slices or zest curls if desired. Serve immediately while firm.