I started by making two 8" chocolate sponges, beating 8oz caster sugar with 8oz butter until it was smooth and creamy and gradually added 4 beaten eggs and 4oz ground almonds and 4oz of sponge self raising flour. I put half in each 8" cake tin and baked at 190C for about 20 mins.
I then made two 8" caramel sponges. I'd already decided I wanted to put some dulce de leche into the mixture but I'd never tried baking with it so decided to rely on good old google and found a recipe on the Pink Whisks' blog here http://www.thepinkwhisk.co.uk/2010/08/caramel-cake.html I followed it exactly apart from adding about 1/2 tsp of salt.
Once both of the cakes were cool I put one caramel one to one side and then sandwiched the other caramel between the two chocolate ones using Dulce de Leche with some added salt and then topped with possibly the lightest chocolate frosting I have ever tasted! The recipe can be found here http://www.ourbestbites.com/2010/05/chocolate-frosting/
I forgot to take a photo before the cake was cut but here's one of a slice so at least got one showing the different layers!
Overall the experiment was a success and everyone was very complimentary. Next time I'd put more caramel between the layers.