1. Pre-heat the oven to 180oC.
2. Sieve the flour and cocoa into a bowl and add baking powder, sugars, corn flour and salt.
3. In a separate jug, combine the milk, apple cider vinegar, sunflower oil and vanilla essence.
4. Slowly add the wet ingredients to the dry until they look silky smooth. An electric mixer works best for this but you can get the same effect with a strong bicep!
5. Pour the mix into a greased 20cm cake tin and bake for an hour and 20 minutes. Leave the cake to cool completely.
6. Thoroughly beat your margarine until completely smooth.
7. Bit by bit add the icing sugar and cocoa through a sieve, beating in-between. You'll make a smooth chocolate fudge frosting.
8. Frost your cake using whatever method you'd prefer (spreading or piping the frosting). We like to add extra chocolate buttons and decorations to ours to make them extra chocolatey!