Preheat the oven to 350° F. Line your cupcake molds with liners.
In a medium bowl, beat together the coconut oil, eggs, sour cream and sugar until combined. Add the bourbon and beat until incorporated. Then add the flour, cocoa powder, baking soda, and salt. Mix until smooth and no lumps remain.
Divide the batter evenly among the cupcake liners (I baked them in two batches). Each liner should be about 3/4 of the way full. Transfer to the oven and bake for 18-20 minutes or until the center doesn't appear soft and wet. Let cool.
While the cupcakes bake, make the frosting. In another bowl (with clean beaters), beat the butter until soft and airy, about 3 minutes. Add the sugar slowly, and taste test as you go to see if you want more or less sugar. Add the vanilla and cinnamon and beat for about 2-3 more minutes, until the frosting appears whipped. The frosting should not be a melted consistency but it shouldn't be rock hard either. Place in the fridge if it needs to stiffen a bit.
Make sure your cupcakes are completely cooled before adding the frosting, as it could melt the buttercream quickly. With a butter knife, frost each cupcake to your liking, around 2-3 tablespoons per cake. Sprinkle cinnamon on top for optional decoration.
Store in an air tight container or place in the fridge if you have leftovers for a few days. However, they probably won't last long! Enjoy!