For the sponge balls you need to mix together 100g s-r flour, 100g butter, 100g caster sugar and 2 eggs into a creamy paste. Divide into 5 bowls and add food colouring. Then divide the mux between a greased 20-hole silicone mould.
Place the cover on top and bake at 180 degrees C for about 20 minutes. When they are cooked and risen and firm to the touch leave them in the moulds to cool and trim any excess and then leave on a wire rack to cool completely.
Meanwhile make the chocoalte cake. Mix together 200g s-r flouir and 35g cocoa powder and add 225g butter, 4 large eggs and 4 tbsp milk and beat. Divide the mix in two and grease 2 17cm cake pans. Put one third of the mix at the bottom of the lined pan and arrange the cooled balls of sponge on top. Then top with the remaining cake mix.
Bake at 180 for about 40 minutes until the cake is risen and firm to touch and a toothpick come out clean. Cool for about 10 minutes then remove from tin to completely cool.
I then melted together 200g chocolate and 200g single cream and used this as the chocolate icing for the cake.
The finished product (covered in smarties)