Preheat oven to 350 degrees.
Start by creaming 1 cup of granulated sugar together with 6 tbsp of softened butter.
Then add in 1 egg, 1 egg yolk and 1/2 tsp of vanilla and combine.
Next mix in 1/2 cup of buttermilk.
In a small bowl sift together 3/4 cup + 2 tbsp of all purpose flour, 1/4 cup + 2 tbsp of dark cocoa powder, 3/4 tsp of baking powder, 1/8 tsp of baking soda, and 1/4 tsp of salt.
Add the dry ingredients to the wet ingredients and combine.
Lastly mix in 1/4 cup of hot coffee.
Line a cupcake pan with 14 cupcake liners and fill each cup 3/4 of the way full. Bake the cupcakes at 350 degrees for 20-22 minutes, or until a toothpick/cake tester comes out clean from the centers.
Let the cupcakes cool in the pan for 5 minutes then transfer to a cooling rack to cool completely.