In the bowl of a stand mixer, mix together all the dry ingredients To the dry mixture, add the eggs, vegetable oil, milk and vanilla and mix on medium speed until well combined.
Reduce the speed to as low as it will go and add the boiling water. Increase speed to high and beat for one minute.
Preheat oven to 180C/350F and grease and lightly flour 2 nine-inch cake pans and 2 6-inch cake pans.
Distribute the cake batter evenly between the cake pans and bake for 24-35 minutes depending upon the size of the pan or until a skewer inserted in the center of the cake comes out clean.
Remove from oven and cool on a rack for 10 minutes and let cool completely before icing.
Vanilla Buttercream : In a mixer, cream the butter 3-5 minutes until light and smooth Add half a cup of icing/confectioner's sugar and beat until incorporated and then add another half cup until all sugar has been used.
Increase mixer speed to high and beat for a minute and then add the vanilla and salt and beat until combined.
Add the milk until the icing is of the consistency you prefer. For softer icing use more milk, for stiffer icing (for piping) use more icing sugar/confectioner's sugar.
Chocolate Buttercream : In a mixer, cream the butter and sifted cocoa powder 3-5 minutes until smooth
Add icing/confectioner's sugar and milk to cocoa mixture by adding 1 cup of sugar followed by about a tablespoon of milk. After each addition has been combined, turn mixer onto high speed for about a minute. Repeat until all sugar and milk have been added.
Add vanilla extract and combine well.
Assembly : Level the layers and spread chocolate buttercream between the layers
Spread vanilla buttercream on the top and sides using piping pour some chocolate butter cream on top and sides or in your ides arrange diary milk shots on side and decorate using kitkat ,ferraro rocher and birthday candy