In a cocktail shaker (or glass), muddle the mint, lime, and agave nectar, if using. Stir in the rum and add the ice. Shake, then strain and pour over the sorbet.
Top with club soda. Stir and garnish with mint, lime, and slices of peach. Cheers!
Notes
What if I don't have mixology tools?
Don't have a muddler? Use a pestle or the end of a wooden spoon!Don't have cocktail shaker? Use a mason jar, thermos or hydroflask!Don't have a jigger/measure? Use a measuring cup!Don't have a tall mixing spoon? Use chopsticks!
Can I use other flavors of sorbet?
Of course. This would be delicious with any fruity sorbet -- raspberry would be amazing.