Mix together melted unsalted butter and melted dark chocolate
In a separate bowl, combine granulated sugar, sour cream or Greek yogurt, eggs, and vanilla extract
Mix the wet ingredients together
In another bowl, whisk together all-purpose flour, cocoa powder, baking soda, baking powder, and salt
Combine the dry ingredients with the wet ingredients
Stir in hot coffee until well combined
Pour batter into a 9-inch cake pan
Bake at 325°F for 75-90 minutes, or until a toothpick inserted in the center comes out clean
Cool cake completely before unmolding
For ganache topping, combine heavy cream with melted semi-sweet chocolate chips and melted salted butter
Top cooled cake with chocolate ganache
