• Preheat oven to 180°C (350º F).
• Line two 20cm (9-inch) round cake pans with baking paper and spray with cooking spray. 
• In a medium bowl, combine the oil, milk, eggs and vanilla extract and mix together.
• In a large bowl, combine the flour, sugar, cocoa powder, salt, baking soda, and baking powder.
• Add the wet ingredients to the dry and mix either by hand or on a low speed of a hand mixer. Don't over-mix.
• Add the water and combine. The batter will be thin.
• Pour the batter into both of the pans and bake for 25-30 minutes or until a toothpick poked into the center comes out clean. Cool for 10 minutes before removing cakes from the pans.
• Allow to cool completely before filling and icing.

Fudge Filling;

• Melt the chocolate.
• Add in the icing sugar and cocoa powder and mix.
• Mix through the softened butter.
• Add in a tablespoon of water at a time. You want the batter thick but pliable.
• Spread over the top of one of the cakes and place the second cake on top.

Chocolate Buttercream;

• Beat the butter and the cocoa powder together.
• Slowly beat in the icing sugar and milk.
• Add more milk as needed until you have a thick and spreadable consistency.
• Spread over the top of the cake and either let the buttercream flow down the sides of the cake for a more rustic look or cover the sides for a prettier look.