Chocolate Sponge

1. Combine oil, eggs and sugar in a mixing bowl and whisk at high speed for 15 minutes.
2. Boil cocoa powder and water until dissolved and set aside.
3. Sift flour, baking powder , baking soda and salt. Add the dry ingredients into the mixing bowl and whisk until combine.
4. Combine milk, water and cocoa powder and add the liquid ingredients into the mixing bowl.
5. Pour the mix into a 20cm round cake tin.
6. Bake at 180°C for 45 minutes.

Chocolate & Orange Ganache

1. Boil the whipping cream with the orange zest.
2. Pour the boiling cream into the dark chocolate together with soft butter and stir until the chocolate is fully melted into the cream.
3. Whisk until smooth and glossy. Let the ganache cool down.

Cake Assembly

1. Horizontally slice chocolate sponge into 2 equal layers.
2. Place one layer on a cake board, spread 1/3 of the chocolate ganache evenly on top of the sponge , and place the second sponge layer over.
3. Spread remaining cream over and around sides of the cake and level.