Its strangely simply to make.
Well firstly it turns out you can cook cake in practically anything! Even rectangle pyrex glass dishes! Thats how I got the main shape for the base of the tank. I then sliced it through the middle using my cake leveler but took a small square section out of the front and back on the top layer of cake to give it the dip where the name plate is.
The round gun turret section was cooked in part of my silicone giant cupcake mould, as this was not too deep. But you could use any small oven proof dish, or make it square and carve it out of sponge.
The Gun is a chocolate ice-cream wafer rolled in icing with a blob of black icing on the end. I have attached it to the cake using a simple drinks straw, but cut off the bendy end if it has one.
To make the door. I used 2 sizes of round cutter to make the green fondant ring, then using the same sized small cutter to make the black bit for the middle and the hatch door. I glued the door on one side using confectioners glue and then rolled some kitchen roll up and placed it under the hatch until the fondant had dried and stays up on its own.
I iced the whole thing in the marbled green fondant first, then added thinly rolled black to the sides, not worrying about how neat it is as you will soon cover the joins with grey fondant for the tracks. I used a knife to add texture to the tracks after adding them to the cake and then cut some more grey fondant circles for the track-cogs.
The finishing touch is melted chocolate on the cake board with some broken up chocolate on top as mud. And dontt forget the sparkler to put in the gun turret!
I used my usual For the basic chocolate sponge recipe for this one. I always use the following recipe as it is so easy to scale up depending on how big your cake is going to be. The basic recipe is:
2oz Self Raising Flour
2oz Caster Sugar
1 teaspoon of cocoa powder
1 teaspoon of chocolate spread
So... to scale up you just use double the oz to eggs, i.e. to make this I would use about 10 eggs and then 20oz of everything else and so on. I use the same recipe for most of my cakes and just add different flavours to it.