Clíona's Amazing Chocolate-Caramel Christening Cake

Hello everyone! I've been a busy little bee the last few weeks - a new job and lots of life-stuff going on. My little niece-to-be had her chistening ceremony recently and her Mum asked me to make a cake I'd made before that she'd really liked. Well - say no more!
I won't lie...2 days went into the decorating of the cake (well, I do have to work too!) but the basic cake itself is very simple and even a novice cook should be able to knock this one out in an evening. The decorating is slightly trickier but there's nothing stopping you from giving it a bash, after all, this is my first attempt of doing anything like this myself.

A word of warning: this is RICH cake. Tiny slices. Seriously. You'll thank me later.

Makes a very tall 8" cake - approx. 12-16 slices

Ingredients
For the Vanilla & Chocolate sponges
225g unsalted butter, softened
225g caster sugar
175g self-raising flour
85g ground almonds
1tsp baking powder
3 eggs
150ml natural yoghurt
1tsp vanilla extract
5tbsp cocoa powder
For the Caramel & Choc-caramel sponges
225g unsalted butter, softened
175g soft light brown sugar
50g dark brown sugar
175g self-raising flour
85g ground almonds
1tsp baking powder
3 eggs
150ml natural yoghurt
1tsp vanilla extract
1tbsp cocoa
To assemble and decorate
1 can Carnation Caramel
1 quantity chocolate buttercream

1. Preheat oven to 180C/Gas Mark 4. grease and line the bases of 2 x 8 inch (20cm) sandwich tins with baking paper. 
2. For the vanilla and chocolate sponges mix all the ingredients, apart from the cocoa,  together with an electric whisk. Transfer half the mix into another clean mixing bowl and whisk in the cocoa. Scrape the mixes into the tins and bake for 20-25 mins until a skewer poked in comes out clean.
3. Repeat this for the caramel and choc-caramel sponges, again reserving the cocoa until you've split the mix between two bowls and whisking it into one batch. Bake as before.
4. Allow the 4 sponges to cool fully on a wire rack.
5. Place the vanilla sponge on a base (or plate) of your choice. Spread a third of the caramel over the base sponge and top with the caramel sponge. Spread another third of the caramel over this and top with the choc-caramel sponge. Spread the final third of the caramel over the choc-caramel sponge and top with the chocolate sponge.
6. Cover the cake in chocolate buttercream and chill in the fridge for an hour.
7. Remove from fridge at least 15 mins before serving.
8. Relax, enjoy, and watch everyone marvel when you cut into the cake and they see the colour graduations of the sponges!