Preheat your oven to 350°F (175°C).
Grease and flour two 9-inch round cake pans.
In a large mixing bowl, combine the dry ingredients: flour, sugar, cocoa powder, baking powder, baking soda, and salt. Stir well.
In another bowl, whisk together the buttermilk, oil, eggs, vanilla extract, and cooled coffee.
Gradually add the wet mixture to the dry ingredients, mixing until just combined.
Stir in the peppermint extract for a refreshing flavor burst.
Divide the batter evenly between the prepared pans.
Bake in the preheated oven for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Remove the cakes from the oven and let them cool in the pans for 10 minutes before transferring them to a wire rack.
While the cakes cool, prepare the frosting by whipping the heavy cream until soft peaks form, then gradually add the powdered sugar and peppermint extract.
Once the cakes are completely cool, place one layer on a serving plate and spread a generous amount of frosting on top.
Carefully place the second layer on top and frost the top and sides of the entire cake.
Decorate with chocolate shavings and crushed candy canes for a festive touch.
Slice and serve the cake at room temperature for the best flavor and texture.