Note: Make sure you have a grown up with you to help with baking!
Method
Preheat oven to 190°C (Gas mark 5/375°F). Grease and line the base of 3 x 20cm round cake tins.
Place the butter and caster sugar in a large bowl and whisk together until well combined and fluffy.
Add the six eggs, two at a time, whisking after you add each pair.
Once the eggs have all been whisked in, add the flour, baking powder, milk and vanilla. Whisk again until fully combined.
Divide the mixture between the 3 tins, gently smoothing the tops down with a spatula.
Bake in the preheated oven for around 20 minutes, until the cakes are golden and springy to the touch.
Turn the cakes out onto cooling racks and leave to cool completely before icing.
Whilst the cakes are cooling, prepare the buttercream icing.
Whisk the butter until soft and fluffy. Add the icing sugar, a little at a time, whisking as you go until completely combined. Add the vanilla extract and whisk again until combined.
Remove approx.. 300g of the buttercream icing and pop it into a separate bowl – this will be used to fill the cake.
Remove another 300g of the icing – this will be used for the crumb coating.
Divide the remaining icing into 4 and colour it in shades of green and blue using the gel food colouring.
When ready to assemble, secure one of the cakes onto a cake board with a little buttercream icing.
Spread over half of the buttercream icing you set aside for filling. Add a second cake and repeat the buttercream filling, then top with the third and final cake.
Using a palette knife, spread the buttercream that you set aside for the crumb coating all over the cake. If you have a cake turntable, this will really help you to get an even coat. Spinning the cake slowly, use a large cake scraper to even out the sides.
Once the cake is covered in the crumb coating, pipe rings of coloured buttercream onto the sides of the cake in rows – light green at the bottom, then darker green, light blue and darker blue on the top.
Using the cake scraper, smooth the icing until roughly even and blended together. Bear in mind you’re going for a seascape effect so it doesn’t have to be perfectly smooth.
Push a ring of sprinkles into the icing a the bottom of the cake.
Shape the green fondant into 2 half hoops, a head and a tail. Paint the edges of edible candy eyes with blue food colouring and pop on top of the head. Place the Nessie pieces on the top of the cake.