Preheat oven to 350 degrees F. Line a muffin tin with 15 cupcake liners.
Mix flour, sugars, baking soda, and salt together and set aside.
Place butter, chocolate, and cocoa together in a bowl and pour boiling water on top. Cover with plastic wrap and let sit two minutes. Mix until smooth and then add in the buttermilk, sour cream, eggs, and vanilla.
Whisk the liquid ingredients into the dry until smooth.
Pour 1/4 cup batter into each paper liner. Bake for 17-20 minutes or until toothpick comes out clean.
Leave cupcakes in tin for 5 minutes before removing onto a cooling rack.
Meanwhile, make the frosting and ganache.