Preheat your oven to 350°F (175°C). Line a 24-cup muffin tin with cupcake liners.

In a medium bowl, whisk together the flour, cocoa powder, baking soda, baking powder, and salt. Set aside.

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

Beat in the eggs one at a time, then stir in the vanilla extract and peppermint extract.

In a separate small bowl, whisk together the buttermilk and cooled brewed coffee.

Gradually add the dry ingredients to the wet ingredients, alternating with the buttermilk mixture, beginning and ending with the dry ingredients. Mix until just combined.

Divide the batter evenly among the prepared cupcake liners, filling each about two-thirds full.

Bake for 18-22 minutes, or until a wooden skewer inserted into the center of a cupcake comes out clean.

Let the cupcakes cool in the muffin tin for 10 minutes before transferring them to a wire rack to cool completely.

While the cupcakes cool, prepare the mocha frosting. In a large bowl, beat the softened butter until creamy.

Gradually add the powdered sugar and cocoa powder, alternating with the cooled coffee, until smooth and well combined.

Stir in the vanilla extract and salt.

Once the cupcakes are completely cool, frost them generously with the mocha frosting.

Sprinkle the crushed candy canes over the frosting.