To make the Plum Ginger Syrup, Combine all ingredients in a medium saucepan. Bring to a boil and simmer for 5 minutes.
Remove from heat and steep for 30 minutes.
Strain the mixture and place in a clear jar.
Cover and store in the refrigerator for up to 1 week.
Combine the bourbon, plum ginger syrup, lemon juice, and orange juice in a shaker with ice.
Shake for 30 seconds.
Strain over a rocks glass filled with ice.
Garnish with a plum slice and a piece of candied ginger.