Preheat the oven to 350°F (175°C) and line a muffin tin with cupcake liners.

In a mixing bowl, cream together the softened butter and sugar until light and fluffy.

Add the eggs, buttermilk, and vanilla extract, mixing until well combined.

In another bowl, whisk together the flour, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Fold in the bourbon and chopped mint leaves.

Divide the batter evenly among the cupcake liners, filling each about 2/3 full.

Bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cupcakes to cool completely before frosting.

In a mixing bowl, beat the softened butter until creamy.

Gradually add the powdered sugar, mixing on low speed until combined.

Add the heavy cream, mint extract, and chopped mint, then beat on high until light and fluffy.

Using a piping bag, frost the cooled cupcakes with the mint frosting.

Garnish each cupcake with a sprig of fresh mint and a sprinkle of crushed ice, if desired.