Combine the cinnamon and sugar in a shallow bowl. In a separate shallow bowl, add 1 tbsp of rum. Dip the rim of a double-rocks glass into the rum bowl followed by the cinnamon-sugar to coat, and set aside.
Add the butternut squash base, remaining 3 tbsp of rum, orange liqueur, simple syrup, bitters and juice of 2 lemon wedges into a cocktail shaker filled with ice and stir, then shake until well-chilled.
Strain into the prepared glass.
*Butternut squash base: Combine 1/2 cup of butternut squash puree (or pumpkin puree), 2 tsp of brown sugar, 1 tsp of molasses and a pinch of salt. Strain the mixture through a fine-mesh sieve into a clean bowl. Use immediately or store in an airtight container for up to 1 week.