To make the simple syrup, use a medium saucepan, combine Water (1/2 cup), Granulated Sugar (1/2 cup), and Fresh Ginger (1 tablespoon). Turn to medium heat and stir until the sugar has dissolved. Remove saucepan from heat and cool completely before adding to the cooler.
In a food processor, add Bourbon (3 fluid ounce), Ginger Simple Syrup (1/4 cup), Rhubarb (1 cup), Fresh Mint (1 tablespoon), Fresh Raspberries (1 tablespoon), Blackberries (1 tablespoon), and Ice (1 1/2 cup).
Pulse until everything is well combined and smooth. Pour into two glasses and garnish with Fresh Mint (to taste).