Preheat the oven to 180C, 160C fan, gas 4.
Mix the eggs, oil, water and cake mix gently together and whisk (by hand or electric mixer) for 2-3 minutes until smooth and creamy.
Divide the mixture evenly between the greased and lined cake tins.
Bake in the centre of the oven for 22-25 minutes or until a rounded knife inserted into the centre of the cake comes out clean, then cool on a wire rack.
Spread half a pot of the vanilla icing onto the top of one of the cakes. Place the other cake on top and sandwich together. Spread the remaining icing over the top and down the sides, fully covering the cake. Smooth round the sides and tops.
Stick the sweets onto the top of the cake. Cut into slices and serve with a selection of the sweets!