You can use any chocolate sponge recipe. You can either make one large cake and cut into four or two medium ones and cut each in half. Or you can make 4 smaller ones which is what I did here.
Begin making the cakes. The two I like for tiers are either a chocolate fudge cake or a yoghurt and oil based cake that is very moist. For the chocolate fudge (which is what I used above) you mix together 100g cocoa powder and 12 tbsp of boiling water. Add 6 large eggs, 100ml milk, 350g s-r flour, 200g soft butter and 400g caster sugar until well blended. Divide between either four greased 20cm sandwich tins or 2 deep 20cm cake tins.
For the yoghurt and oil cake the recipe is as follows. Since it replaces the butter with the yoghurt and oil it is a very light cake.
Being mixing 500ml of sunflower oil with 300g caster sugar.
Then blend in 450ml of yoghurt.
Add to this 4 eggs, 450g of self raising flour, 4 tsps baking powder, 4 tsps of vanilla extract and 3 tbsp of cocoa powder (you can omit the cocoa if you want a plain rather than chocolate sponge).
Whisk til combined,
Line four sandwich 20cm tins (or two 20cm cake tins) and divide the mix.
Bake at 160 degrees for about 35 mins til risen and cooked through.
Allow to cool. Meanwhile make the icing. You want something fluffy and yet firm enough to pipe. I've been using this butter icing made with double cream. You can use usual butter icing. For the one I made I used royal icing powder to give a stiffer finish.
Cream 175g butter for about 7 minutes until it is creamy and fluffy and nearly white. Then beat in 300g icing sugar for about 3 minutes and then 1 tsp vanilla extract and then add in about 175ml double of double cream and beat for another 5 minutes. You can play around with the amount of cream- the less you add the stiffer it will be- the more you add the fluffier. This is enough for 24 cupcakes but you make need more for this cake depending on the size of your piping nozzle.
You can also use a pot of double cream whipped together with a cup of icing sugar for some of the middle layers. Or you can use a chocolate fondant (100g of chocolate and 60g double cream melted together) for some of the layers.
Put one cooled sponge on a plate or board (use some cream to hold it) and pipe over the icing. Put a sponge on the top and repeat. The top layer you want to have the neatest icing since that it the one that you can see. Since it was Easter I decorated with different size eggs and some edible gold lustre and purple glitter but you can decorate however you wish.