Grease a large bundt tin (or cake tin) and set aside.
Sift the flour, sugar, cocoa powder, baking powder, bi-carbonate soda and salt into a bowl and set aside.
Using beaters or a stand mixer, mix the buttermilk, oil, room temperature eggs and vanilla in a large bowl until well combined.
Slowly add all of the dry ingredients to the wet ingredients with the mixer on low.
Pour in the coffee and mix until well combined.
Pour the batter into the prepared tin and bake for approximately 35 minutes or until a toothpick inserted in the center comes out clean (don't overcook the cake - you want it to be nice and fudge-like!).
Allow to cool completely.
To make the frosting beat the butter on high speed until smooth and creamy.
Reduce the speed to low and slowly add in the icing sugar as well as the cocoa powder. Beat until combined.
Turn the mixer up to medium speed and add in the vanilla extract, milk and salt. Beat on high speed for 1 minute.
Spread the frosting over the cake and decorate with fresh raspberries (optional).
Store in an airtight container at room temperature for 3-4 days.
Please note that keeping the cake at room temperature will result in a beautiful, moist texture.