Preheat oven to 140°C (280F). Position a rack on the second lowest shelf of the oven. Brush a round 25cm (base measurement) cake pan with the melted butter to lightly grease. Line base and sides with non-stick baking paper.
Place the self-raising flour, plain flour, sugar, butter, milk, eggs and vanilla essence in a large mixing bowl. Use an electric beater to beat on low-speed for 30 seconds or until just combined. Increase the speed to high and beat for 1-2 minutes or until the mixture is thick and all the butter is incorporated.
Split the mixture into 3 bowls evenly. In the first bowl shift the cocoa powder into the mixture and stir/beat until combined. This is your chocolate cake. Move onto the next bowl, add around 3-4 drops of green food dye, mix it in and see what your colour is like! For this bowl you are going for a lighter green colour. I recommend trying to get the light colour sorted first, if you accidentally slip and add too much green food colour, you can always use this as the darker coloured green! Once you have the light one sorted move onto the brighter green. For this one go with 6-8 drops of food colouring. Mix it in and compare to your light green colour. There should be a marked difference between the two. Don’t worry if it’s really bright – this will just make it more fun!
Ok now you are ready to start layering your cake. Grab your prepared cake pan and 3 teaspoons. Begin by spooning lumps of alternating coloured cake mix into the base of the cake pan. Continue to layer until all of the 3 mixtures have been used. With a clean teaspoon smooth out the top of the mixture, at this point you can swirl some of the colours together to integrate the top of the cake. Don’t mix too much – just enough to smooth the top of the mixture out.
Bake in preheated oven for around 1 hour or until a skewer inserted into the centre of the cake comes out clean. Remove from oven and set aside for 10 minutes. Turn onto a wire rack for 2 hours or until completely cool.
To complete your cake, you’ll need to ice it (well you don’t have to! It does seem like a shame to cover up that amazing looking top!), but if you want fatten up your cake eaters then I suggest a butter cream icing! In a bowl combine the butter and icing sugar, add in the melted chocolate and combine until smooth. This can at times take some balancing – if your icing is too thick and a tiny bit of milk. If it’s too thin add a little icing sugar until you get the mix right. Using a pallet knife smooth your icing on top of the cake. You can pick up little plastic army men to top your cake with as decoration and most of all enjoy!
