For the cake:
1. Preheat the oven to 180°C.
2. In a medium sized bowl, sieve the dry ingredients, leaving out the chocolate chips, together and set aside.
3. Whisk the wet ingredients together, then fold them into the dry ingredients until smooth and no lumps remain. Be sure to not over-mix.
4. Fold in the chocolate chips and pour the batter into two greased baking tins.
5. Bake for 25-30 minutes, or until a skewer comes out clean after inserted into the center of the cake.
6. Allow the cake to cool down completely before icing.
For the icing:
1. With an electric mixer, beat the butter until smooth. Slowly add the icing sugar with the mixer on a low speed until complete incorporated.
2. Add the cocoa powder, vanilla essence and milk to the icing and turn the speed up, allowing the mixture to beat for 3-5 minutes.
3. Remove from the mixer and ice the cake, sandwiching the two layers with icing.
4. Slice and serve.