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 granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the buttermilk, bourbon, and chopped mint leaves.

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

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

Divide the batter evenly among the cupcake liners and bake for 20-25 minutes or until a toothpick 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 well.

Add the heavy cream, vanilla extract, and peppermint extract, and beat until fluffy.

If desired, add green food coloring to achieve a minty color.

Frost the cooled cupcakes with the mint frosting.