In a medium sauce pot, combine sugar, water, and mint leaves. Bring to a boil until sugar has dissolved. Remove from heat. Cover sauce pot and let mint steep for 10-15 minutes. Taste, if syrup has enough mint flavor, strain out mint leaves, otherwise steep for another 5 minutes or so. Allow syrup to cool to room temperature. Transfer to air tight container and keep chilled in the fridge until ready to use.