Having never made a decorated cake before in my life and not being a huge baker did not give me pause. I've taken a lot of crafting courses over the years and am comfortable working with a variety of tools. There was no question in my mind it would be a challenge, but I felt with the right planning I could do it.
Over the weeks I collected four boxes of gluten-free cake mix. Chocolate. Of course! I purchased four disposable 8x8 cake pans. Then I ordered the fondant and got supplies for icing. To get the shapes I wanted I bought a heart cookie cutter and a cross. The cross was incredibly useful to create the corner pieces. In the end the heart was only useful for the top piece. I needed smaller hearts for the sides. For the circles on the companion cube I ended up using a wine glass and for the large, top circle I used the lid from a container of Smart Balance.
Here's the cake! I simplified the design, leaving out the pink lines and the smaller corner pieces. To be honest I was worried about ruining the silver icing color and did not have the right tool to pipe out icing. Each cake inside has a layer of icing between it and the next cake and there's icing on the outside to hold the fondant to the side.
I used Ener-G egg Replacer to replace the three eggs per cake that the recipe called for. It worked beautifully, as usual.
So, rest tight little cube. You'll be decimated soon! Muhahahah!