Pre-heat your oven to 350F (conventional) and prepare a 9" cake pan with parchment paper and butter / oil
If making your own buttermilk, mix ½ cup milk with ½ tbsp vinegar, stir, and set aside
Mix the flour, sugar, baking powder, baking soda, and salt in a bowl. Sift the ingredients to make sure there are no lumps
Break in the egg, and add the vegetable oil and buttermilk. Use a whisk to gently mix until the ingredients come together
In a smaller bowl, mix boiling water with cocoa powder and instant coffee, and whisk until you get a shiny mix. This step blooms the cocoa powder and brings out its lovely chocolatey notes
Add the bloomed cocoa powder mix to the cake batter, and gently fold until combined
Pour the batter into the prepared pan
Bake at 350F for about ~20-25 minutes until a toothpick inserted into the center comes out with moist crumbs attached
Wait 10 minutes and then turn out the cake onto a wire rack
Bring the cream to a boil, and pour over the chopped chocolate. Cover and rest for 5 minutes to allow the chocolate to melt, then mix until you get a shiny ganache. Rest for another 5 minutes so the ganache thickens slightly
Pour the ganache over your cake, and you're ready to dive in!
