Companion Cube Cake

Although I’ve never played Portal, I think that the concept is intriguing. It’s set in a science laboratory and the main character is challenged to complete a series of puzzles, with the promise of receiving cake as a prize. The companion cube accompanies the character on her journey.

The Boyfriend requested that I make a companion cube cake for his birthday. I love the idea of a cube-shaped cake so it was a fun project to complete. I used buttercream, my favorite edible artistic medium, since we rank taste right up there with looks. Fondant just can’t come close to the taste of real buttercream!

I started out with three layers of 8″ round chocolate cake, with buttercream in between the layers. Never mind that the cake layers are all of different heights. I had some technical difficulties while baking. But the height actually turned out just perfect for the size cube I was making. And what size cube might that be? A little bit of math (and a lot of plain old approximation) helped me decide where to cut the rounded edges off.

Since the temperature of my kitchen on this day was 76°F, the buttercream in between the layers was beginning to melt at this point. So I popped the cake into the fridge for about 10 minutes. This happened frequently during the course of making this cake.

Next, the cube got a crumb coat of frosting. This is just a super thin layer of frosting meant to capture all of the crumbs so that they don’t make an appearance in the final coat of frosting. After the crumb coat, the cake goes into the fridge for another 10-15 minutes to allow the buttercream to harden a bit. That way, the top coat of frosting can be applied over the crumb coat, without the crumbs getting blended in.

The gray color that I used was created by adding small amounts of black gel food coloring to the buttercream. It’s very easy to make the frosting too dark so be patient when adding color. A little bit goes a long way! Once the cake has been frosted, it goes back into the fridge for about 15 minutes to harden.

It’s not very tricky to smooth buttercream, since the heat of your hands melts the butter instantly. I placed a sheet of wax paper over the chilled surface of the frosting and ran the palm of my hand gently over the wax paper. To get the corners sharp, I folded the wax paper over the edge of the cake and used both hands to smooth the icing toward the corner.

The decorations for the five panels are all the same, except that the heart is rotated on each side of the cube. Only two other colors are required to complete the design, a light gray and pink. To make the light gray, I added just a touch of black gel food coloring to the buttercream. To make the pink, I used a small amount of red gel food coloring. I used a flat icing tip (Wilton tip #47) to add the light gray accents, and a basic round tip (Wilton tip #3) to add the light gray circles and the hearts.

I’m pleased with the way this cake turned out, and The Boyfriend and I found it to be extremely tasty!