Preheat your oven to 350°F and prepare two muffin tins with cupcake liners.
In a large mixing bowl, combine cake mix, water, oil, bourbon, and eggs until thoroughly mixed.
Fill the cupcake liners a little over ⅔ full with the batter. If you only have one muffin tin, refrigerate the remaining batter and repeat the process for the next batch.
Follow the baking instructions on the cake mix box, typically around 15-20 minutes.
Allow the cupcakes to cool while you prepare the frosting.
In a medium saucepan over medium heat, melt butter. Add brown sugar and stir frequently until it reaches a boil. Reduce heat slightly and simmer for 6-7 minutes, stirring often.
Remove from heat and mix in milk. Let the caramel mixture cool completely.
Once cooled, beat the caramel mixture with powdered sugar until frosting forms. Adjust consistency with additional powdered sugar (to thicken) or milk (to thin) as needed, adding 1 to 2 tbsp. at a time.
Pipe the frosting onto the cupcakes and sprinkle with mini chocolate chips. Enjoy!