My friend and colleague Neil asked me to make his son’s 5th birthday cake, in the shape of his favourite lego piece. The boy has excellent taste — his favourite piece is a lego computer. I thought I’d document how I went about it in case it’s of use to anyone else πŸ™‚

First of all I made a vanilla buttermilk cake in a large roasting tin so it was about 38cm long, 24 cm wide and 6cm deep and a bunch of vanilla buttercream icing.

Then I took the photo of the lego computer piece and measured it to make sure I got the proportions of the slope etc right. I multiplied out the ratios and matched it to the available cake:

Picture of lego computer piece and calculations of the ratios of the various parts

I cut the oblong cake into a 2/3rd and 1/3rd piece and placed one on top of the other. I then carved a triangle out from the bottom to make the correct slope. With the remaining couple of pieces I made the lego studs (apparently that’s the correct term for the bumps on top of lego) for the top.

Cake carved so it is like a cube, but with a side cut away in a slope

Next I covered this in a thin layer of buttercream icing — not worrying too much if any crumbs got into the icing. The key thing was to get a smooth layer, both for the fondant to stick to and to even out the total shape. Important to get this right as the fondant is very unforgiving — any bumps will show through!

Basic shape of lego computer cake iced in buttercream

Next I rolled out a couple of packets of white fondant icing and draped it across the entire shape, using a polisher to get sharp edges. I also used the back of a sharp knife to trace around the base of the bumps to make them stand out right.

Lego cake covered in white fondant layer

And then finished it off with coloured fondant to create the screen and buttons πŸ™‚

Lego computer cake with green screen and "Dylan = 5" written in blue fondant