Preheat oven to 180ºC (356ºF). Line a round 8 inch baking pan with parchment paper, set aside. NOTE: Alternatively, if you have a non-stick pan, liberally grease it with melted butter and dust it with a light layer of cocoa. This will leave your finished cake with smooth sides.
In a medium size mixing bowl, add flour, cocoa, baking powder, coffee and salt. Whisk until well combined. Set aside.
In a large mixing bowl, using either electric hand beaters or a stand mixer with the paddle attached, add softened butter to the bowl.
Beat butter for a few seconds to break it up and it begins to turn creamy. This makes it easier on your beater when the sugar is added.
Add sugar. Beat with the butter for 2 minutes until pale and creamy. Scraping down the sides as needed.
Add eggs one at a time, beating for 10 seconds after each addition. Scrape down the sides as needed.
Pour in milk, oil and vanilla. Beat for 15 seconds until well combined. Scrape down the sides again.
Add half of the dry flour mixture and beat until just combined. Scrape down the sides and add remaining flour. Beat until incorporated, ensuring not to over-beat, just until the flour has combined then turn off the beater. If some excess flour and cocoa is still visible around the sides of the bowl, gently fold it in with a spatula. If you over-beat, the cake can turn tough and dense after baking.
Pour into lined pan and smooth out the top with a spatula.
Bake for 30-35 minutes, or until a skewer inserted into the middle comes out clean and it’s golden all over.
Remove from oven and allow to cool in pan for 10 minutes.
Carefully remove from pan and transfer to a wire rack to cool completely.
Break chocolate down into squares and place into a small heat-proof bowl.
Pour cream into a small pot and gently warm over a low heat.
Heat cream until warm and steam starts to come off the surface and small bubbles begin to appear around the edges, do not let it come to a boil. Remove from heat.
Pour warm cream over chocolate and let sit for 2 minutes.
Gently stir chocolate into warm cream until well combined and smooth.
Set aside at room temperature for 30 minutes until it has thickened up to a spreading consistency. Or refrigerate until it firms up. Keep a close eye on it though, once it thickens and reaches a spreading consistency, it will turn solid quickly and at which point, it will be difficult to spread.
Spread frosting over cooled cake. Set aside and allow to set.
Slice into triangles and enjoy.
Store in an airtight container, in a dry dark pantry, for 3-4 days. Transfer to the refrigerator after a few days if needed to keep it fresh from humid temperatures.