Preheat the oven to 350°F. Grease the cupcake pan with butter or fill the pan with cupcakes liners.
In the bowl of your mixer, mix together the eggs, canola oil, vanilla extract and buttermilk until combined.
In a separate bowl, mix together the flour, brown sugar, granulated sugar, baking soda, baking powder, and salt.
Add in the dry ingredients to the wet ingredients in three batches, alternating with the cream soda. Mix everything together on low.
Pour the batter into the cupcake pan, filling each tin about ¾ full. You will have to do this twice if you only have one pan. Bake in the oven for 18-20 minutes. Let cool completely before frosting.
Make the frosting: beat the butter in a mixer until whipped, about 1 minute. Then add the bourbon, powdered sugar and vanilla extract and beat for another 1-2 minutes.
Make the butterscotch. Heat the butter in a small saucepan over medium heat until melted. Then add the cream, brown sugar, vanilla extract and sea salt. Bring to a boil for 4 minutes and stir frequently. It should become thick. Remove from the heat and let cool for 5-10 minutes.
Frost each cupcake evenly and drizzle with the cooled butterscotch. Sprinkle on additional sea salt and enjoy!
