In a double old-fashioned or sterling julep cup, muddle the mint leaves to release their oils.
Add crushed ice to the top of the glass. Pour in the bourbon and simple syrup. Stir well. Garnish with fresh mint sprig.
For the best cocktail, keep your glassware in the freezer prior to mixing. You can always add more bourbon. We don't judge.
For batch cocktails- triple the amount of each ingredient, add to a cocktail shaker with ice, and then pour over your crushed ice in the julep cups.