In a chilled julep cup or fizz glass, muddle the mint leaves and the Simple syrup. Add the bourbon and crushed ice. Set a swizzle stick of bar spoon between your hands to mix. Tops with additional crushed ice and garnish with mint sprigs.
Notes
I don't have a julep cup or fizz glass so just used my Bailey's glass. Also no muddler so used a pestle to grind the mint leaves with the syrup. Tasted fantastic!