Preheat your oven to 350 degrees F (175 degrees C) and grease three 8-inch cake pans, lining them with parchment paper.

In a large bowl, whisk together the flour, cocoa powder, sugar, baking soda, baking powder, and salt.

In a separate bowl, whisk together the eggs, buttermilk, vegetable oil, and vanilla extract.

Combine wet ingredients with dry ingredients and mix on medium speed, gradually adding the hot coffee until a smooth batter forms.

Divide the batter evenly among the prepared cake pans and bake for 28-32 minutes, or until a toothpick comes out with moist crumbs.

Let the cakes cool in the pans for about 15 minutes, then invert them onto wire racks to cool completely.

Beat the softened butter until fluffy, then gradually add the powdered sugar, peppermint extract, and heavy cream until smooth.

Layer the cake with buttercream between each layer and apply a crumb coat, then chill briefly.

For the ganache, heat the heavy cream until it simmers, then pour it over the chocolate chips and espresso, whisking until smooth.

Once the ganache cools slightly, pour it over the top of the cake allowing it to drip down the sides, then decorate with crushed candy canes.