Preheat the oven to 375f and grease and line two 8 inch cake tins.
Sieve the flour and cocoa into a large bowl.
Whisk together the sunflower oil, soya milk, vanilla extract and maple syrup then slowly add into the flour mixture stirring constantly until you have a smooth batter.
Pour the batter evenly between the two cake tins then place into the oven to bake for around 40 minutes until a toothpick inserted in the centre of each cake comes out clean.
Allow to cool in the tins for ten minutes then turn out onto a wire rack to cool completely.
To make the frosting, sieve the icing sugar and cocoa powder together. With an electric whisk, beat the vegan butter until light and fluffy then gradually add in the sifted icing sugar, cocoa powder and soy milk. Whisk until you have a smooth buttercream.
Spread the frosting on top of the base of the cake then top with the other half.
Spread more frosting on top and decorate with shaved dark chocolate or pipe the remaining buttercream over the top and sides of the cake as i have done here.