Preheat oven to 175C (350F) and line two 8″ (20 cm) cake tins with baking paper.
In a large bowl, sift the flour, sugar (yes the sugar – enhances the texture), cocoa, baking powder, baking soda and salt. Whisk well and set aside.
In a separate bowl, mix together the buttermilk, canola oil, eggs, and vanilla. Gently stir this in to the dry mixture until just combined. Then add hot water and mix until well incorporated (but try not to over mix).
Pour cake batter evenly into cake tins (I like to use scales to get both layers perfectly even) and bake for 30 minutes or until skewer comes out clean when inserted into the cake.
Once cakes are slightly cool, transfer cakes to a cooling rack. Once completely cool, whip up your favourite buttercream (or the one suggested – I love adding chocolate ganache to it). Level cakes with a bread knife and ice/frost.