Preheat oven to 180°C and line two 20cm round baking tins with canola oil spray and baking paper.
Using an electric mixer, cream the butter and sugar until lightened in colour and thickened. Add the eggs one at a time, beating well after each addition. Add the vanilla essence, flour and milk and fold until just combined.
Evenly spoon mixture into tin the two tins and bake for 45-50 minutes until a skewer inserted into the middle of the cake comes out clean. Cool in the tin for 5 minutes and then transfer to a cake cooling rack and allow to cool completely.
Stack the two cakes on top of each other, on the cake board that the cake will be served on. Gently cut around the top layer to form a skirt shape, approximately 2cm off the top corner of the cake.
To make the icing, cream the butter and sugar using an electric mixer and gradually add the boiling water. Whip until light and fluffy and sugar cannot be felt when icing is tested between two fingers.
Begin to ice the base of the cake, using a pallet knife and when you have nearly reached the top, place Barbie’s torso approximately 1.5cm into the centre of the cake. Continue to ice around Barbie until the icing is smooth and even.
Decorate using any edible items you, or the birthday girl like.
