Place simple syrup, lime juice, and mint, in a high-powered blender and mix for 1 minute. Add rum and ice and continue to blend until completely smooth and frothy. Immediately pour in glasses; garnish with mint and lime slices. Enjoy!

Simple Syrup:

In a small saucepan, bring water and sugar to a boil stirring constantly. Once the sugar is dissolved completely, add mint (if using) reduce the heat, cover, and simmer for 2 minutes. Remove from heat and let syrup steep, about 30 minutes.

Discard mint leaves and pour syrup into a glass bottle or jar; let cool. Store in the in the refrigerator for up to 3 months.