Muddle lemon slices, blackberries and mint in a cocktail shaker. Add bourbon and simple syrup and fill shaker with ice. Shake at least 10 times and strain into a short glass filled with ice.
Garnish with mint.
Notes
I make at least a cup of simple syrup at a time; having it on hand in the refrigerator instead of having to make it and wait for it to cool is a great timesaver.Simply combine equal amounts of water with sugar and heat until the sugar dissolves. Chill before using in a cocktail.My quick and dirty method? Mix one half the amount of water with the sugar and warm until the sugar is melted. Pour that mixture over the other half of water...in the form of ice cubes! Instant simple syrup.