Brush an 8” round cake pan with melted butter and line the bottom of the pan with a round piece of parchment paper, brush the parchment paper with melted butter as well. Set aside.
In a large mixing bowl, whisk together coffee and buttermilk. Whisk in the vegetable oil, then egg and vanilla. Beat until thoroughly combined.
Transfer the cake batter into the prepared cake pan and bake for 30 - 35 minutes until a toothpick inserted in the middle of the cake comes out clean with just a few crumbs attached.
Put the cooled cake on a cake stand or plate and drizzle the ganache over the top of the cake, tap the cake stand or plate lightly on the table top to even out the top of the ganache. Serve right away or let the ganache thicken further in the fridge before serving.
One Bowl Chocolate Cake https://therecipecritic.com/chocolate-cake/