To Make The Cupcakes:

1. In the bowl of stand mixer, cream butter and sugar until light and fluffy. Add eggs, one at a time, beating well after each addition. Add in vanilla.
2. In a separate bowl, whisk together the flour, cocoa, baking soda and salt until combined. Then in an additional separate bowl, stir together buttermilk and coffee. Add dry ingredients to creamed butter mixture alternately with buttermilk and coffee, beating well after each addition.
3. Fill paper-lined baking cups two-thirds full. Bake at 375° for 15-20 minutes or until a toothpick inserted near the center comes out clean. Cool for 10 minutes before removing from pans to wire racks to cool completely.
4. Top with chocolate ganache frosting, then sprinkle with sea salt.

To Make The Ganache Frosting:

1. Place the chopped chocolate in a small heat-proof bowl.
2. Heat the cream in a small saucepan until it just reaches a boil. Remove from heat and immediately pour over the chocolate. Stir slowly until the chocolate is completely melted and the mixture is smooth. Let it cool until it reaches room temperature, about 1-2 hours. It will continue to thicken the longer it sets.
3. Spoon or pipe the ganache onto the cupcakes. If the ganache is too thin for piping, you can transfer it to the bowl of a stand mixer and beat it on medium-high for 3-5 minutes until it reaches a better consistency for piping.