To make the shrub
Add all ingredients to a glass container (I used a mason jar), seal, and shake to combine.
Put the jar into the fridge for 24 hours.
After 24 hours, shake to recombine and strain the solids through a sieve (it's okay if some of the puree makes its way through). The shrub will keep in the fridge for about 2 weeks.
Add bourbon, pumpkin shrub, and maple syrup to a rocks glass.
Stir to combine.
Add ice and top with ginger beer.