Pre-heat your oven to 160C Fan/180C/350F/Gas Mark 4, and grease and line three 8" cake tins (that are at least 2" deep)
Make the sponge by mixing the butter and caster sugar in a large bowl with an electric mixer until fluffy (about 2 minutes)
Add the eggs and milk, and whisk until fully incorporated
Add the self raising flour, cocoa powder and baking powder and whisk in just until you can't see any flour anymore
Divide the mixture between the tins, use scales for accuracy
Bake them for 35-40 minutes or until a skewer inserted in the middle comes out clean. Leave them to fully cool either in the tins or remove from the tin and place on cooling racks
To make the chocolate buttercream mix the butter, cocoa powder and icing sugar together. Once it starts to come together add the milk and mix until smooth. Use an electric mixer for the best results. You can add more milk if the buttercream is too stiff
To make the dark chocolate ganache, put the ingredients into a bowl and microwave for 20 seconds, then stir. Continue microwaving in 10 second blasts, stirring between each blast, until melted and smooth
OR To make the cheat's dark chocolate drip, melt the dark chocolate in the microwave for 30 seconds, then stir. Continue microwaving in 10 second blasts, stirring between each blast, until melted and smooth. Stir in the vegetable oil
See the rest of the post for decorating instructions. Store in the fridge and in an airtight container once cut