Preheat the oven to 180 degrees

Butter and line two 10 inch sandwich tins (or smaller if you don't want a Matilda-esque cake)

In a large bowl mix together the flour, sugars, cocoa, baking powder, bicarb and salt.

In another bowl or wide-necked measuring jug whisk together the eggs, sour cream and vanilla until blended.

Using a freestanding or handheld electric mixer beat together the melted butter and corn oil until just blended then beat in the water.

Add the dry ingredients all at once and mix together on a slow speed. Add the egg mixture, and mix again until everything is blended and then pour into the prepared tins.

Bake the cakes for 50-55 minutes, or until a cake-tester comes out clean. Cool the cakes in their tins on a wire rack for 15 minutes, and then turn the cakes out onto the rack to cool completely.

Melt the chocolate in the microwave - 2-3 minutes on medium should do it - or in a bowl sitting over a pan of simmering water, and let cool slightly.

In another bowl beat the butter until it's soft and creamy and then add the sieved icing sugar and beat again until everything's light and fluffy. Then gently add the vanilla and chocolate and mix together until everything is glossy and smooth.

Sandwich the middle of the cake with about a quarter of the icing, and then ice the top and sides too, spreading and smoothing with a rubber spatula.

Next is the fun part, you could add any decorations you please but I find KitKats are a really sturdy support around the cake and stop any of the top decorations sliding off. Chocolate fingers would also work but not on a cake of this size, you would have to downsize if you decide to use those.

Decorate your cake by sticking the Kit Kats around the outside to your already iced cake, then use chocolate fingers to divide the cake into four triangles, add the mini eggs to two of the triangles, and the minstrels and Maltesers to the other two. You can then remove and eat the chocolate fingers or push them into the cake so they can't be seen.