Muddle together syrup, lime and mint leaves. Stir in rum. Fill glass halfway with ice. Top with club soda (use lime flavored soda if you like your mojito extra limey). Garnish with additional mint leaves or lime wedge as desired.
Mint Simple Syrup
Add water, sugar and mint leaves to a small saucepan. Bring to a boil over medium high heat. Remove from heat and steep for an hour. Strain into a bottle or jar and cool completely before using. Can be stored in fridge for several months.