Giant Lego Cake

All the stuff I used in today's video:
1 batch vanilla cake (recipe below)
1 batch buttercream (recipe link below tinted yellow)
2 packets yellow candy melts
10 mini Oreo cookies

Vanilla Cake Recipe:
260g / 9oz Plain flour, sifted
225g / 8oz Caster sugar (USA - granulated)
250g / 8.8oz Butter, softened
110g / 3.8oz Whole milk
3 x 65g/2.2oz Eggs, room temperature (ex-large)
40g / 1.4oz Vegetable oil
3 tsp Baking powder
1/2 pod Vanilla bean pod
Method:
Preheat oven to 350f / 180c (fan) / Gas Mark 4
Place butter, sugar, vanilla and eggs into a mixing bowl
Beat on high speed with an electric mixer (whisk or
paddle attachment) until ingredients are well combined
and appear light and fluffy (approx 1 -2 minutes)
Cut the vanilla bean pod lengthways down the centre
and split it in half. Using the tip of a sharp knife, scrape
the tiny seeds from inside the vanilla bean
Add oil and vanilla seeds to creamed mix and combine
Combine baking powder and flour together and stir
Add flour, baking powder and milk to creamed mixture
Beat on high speed until flour is completely mixed
through (approx. 30 seconds - 1 minute)
Pour the mixture into a Loaf tin (I used an Ikea Bullar Loaf Tin; dimensions 26 cm Height: 7 cm Width: 12 cm Volume: 1.3)
Place onto the middle rack of a moderate oven and cook for 35-35 mins (fan forced) or 45-55mins (non-fan)