Preheat oven to 350°F and line 2 muffin tins with cupcake liners and set aside.
In the bowl of a stand mixer fitted with a paddle attachment, combine flour, sugar, cocoa, baking powder, baking soda, and salt. Whisk to combine.
In a large measuring cup or bowl combine the buttermilk, oil, eggs, and vanilla. Whisk to combine.
With the mixer on low, slowly pour the liquid ingredients into the dry ingredients.
Then pour the hot coffee into the batter. Mix until just combined.
Fill cupcake liners about 2/3 of the way full.
Bake in preheated oven for about 18 minutes, until a toothpick inserted into the center comes out clean.
Remove cupcakes from oven and allow to cool completely before frosting.
In the bowl of a stand mixer fitted with a paddle attachment, cream butter on medium-high speed until light and fluffy, about 3 minutes.
Reduce mixer speed to low, and add the powdered sugar, about 1/2 cup at a time, until thoroughly combined.
Add the vanilla and peppermint extracts and a pinch of salt and increase speed on mixer to medium.Beat for 1 minute.
Frost cupcakes as desired, and garnish with crushed peppermint candies.