Transformers Cake – Bumblebee and Optimus Prime Birthday Cake

Here is a simple Transformers cake I decorated for my nephew’s 6th birthday over the last weekend. The Transformers theme was his choice of course. And he likes Bumblebee the most, hence the yellow and black overall theme for his cake.

Simple Transformers Cake – Bumblebee and Optimus Prime Birthday Cake

I call this a simple cake for 2 reasons. Firstly, it was a relatively small single tier cake measuring 8 inches by 8 inches in width and length, and a height of about 3 inches. Secondly, it was decorated with basic piped buttercream design and topped with a printed edible image of Transformers. All this did not require as much time, hence a pretty simple decorating idea.

I was not the one who baked this cake. It was baked by my sister (my nephew’s mom) and she sought my help in decorating the cake. I have shared my cake recipes with her. So the cake was baked using my butter pound cake recipe (this is our family favorite!). She also got the edible image ready (from a local shop). And even got the buttercream mixed. So all I had to do was mix in the colors and decorate the cake. 

The cake itself was a single layer cake, and there was no filling inside. My sister preferred it that way. And so, all I did before decorating the cake was crumb coat it so that the sides and top were all level.

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How to Make a Simple Transformers Cake

Main supplies for the cake:

• Cake – This was an 8 inches by 8 inches square cake baked in a single cake tin. 
• Buttercream –  I used buttercream to crumb coat the cake as well as to decorate it.
• Edible Image – this was ordered from a local image printing shop. The image was chosen by my sister from the internet. She requested it to be custom printed on a sugar sheet.
• Sugarcraft knife – I used this knife to cut out my nephew’s name from the edible image sheet. The name, as it came from the supplier, was printed together on a rectangle piece of the image. Since the size would not fit the cake, I had to cut it into two.
• Edible gold dragees
• Wilton golden yellow and Americolor black food coloring
• Wilton star tip number 18
• Disposable piping bags
• Wooden skewer and clean ruler – I used these to help me in marking the squares on the cake. 

Simple Transformers Cake

Assembling the Transformers cake:

Preparing the cake

• Since I did not bake the cake, when my sister delivered it to me for decorating, she had already placed it on a cake board ready to be frosted. She chose a black cake board. That matched her yellow and black theme so there was nothing else needed to be done for the cake board.
• I even got her to mix the buttercream (which she did following my recipe here) and so I started the decorating work with a base crumb coat for the cake. The top of the cake was not quite level, and even the sides needed a little fixing. So I gave the cake a base coat of buttercream until the sides and top were all level.

Transformers edible image

• And then, I cut out the Transformers image and placed it right in the center of the cake. I did not use any ‘glues’ to attach the image to the cake as the buttercream was able to hold it well in place.

Simple Transformers Cake

The square designs on the cake

• After that, I marked the square patterns on the cake. I started with the sides and then continued on top. For the sides, to make sure I got equal-sized squares, I measured and marked them before starting the piping work. For each side of the cake, I divided them into 4 squares. Once I had all the 4 sides marked, I followed the same pattern on the top of the cake, stopping the marks at the border of the image. 
• For the top corners, I marked them into triangles instead.

Mixing the colors

• Next, I mixed the colors into the icing. I colored all the remaining icing in yellow first. I filled the icing in a disposable piping bag fitted with star piping tip number 18 and started piping.
• For each square, I started piping the lines continuously from the outer edge all the way until I reached the center and the square all covered in buttercream. In piping the lines, I made sure they were piped close to one another so that there is no gap in between them that could show the crumb coat underneath. 

Buttercream decoration in yellow and black on the sides of the Transformers birthday cake

• I completed all the yellow piping before moving on to the black. I added black food color into the remaining yellow icing (and the icing turned black), filled it into another piping bag that was fitted with the same star tip number 18. Similar to the yellow squares, I started from the outer edges of the squares to the centers and completed the sides of the cake before moving to the top.

The black and yellow buttercream design on the sides of the Transformers Cake

• I did not add any border for the Transformers cake. This was because the squares piping was pretty neat. I felt that it looked good that way already.

The birthday boy’s name

• The next step was the birthday boy’s name. I cut the name from the edible image sheet my sister gave me and placed it on the birthday cake. Again, no ‘glue’ was required for the name to stick to the cake. The buttercream held it well in place.

The birthday boy’s name in edible image on the Transformers Cake

Edible gold dragee frame

• And finally, for the finishing touch, I added a row of gold dragees all around the Transformers edible image, framing it nicely on the cake. Also, I did not use any ‘glue’ to hold them in place, I merely pushed them against the buttercream around the image and they stayed in place. 

The gold dragee frame on the Transformers birthday cake

With that, my simple Transformers cake was ready.

This was the party dessert table at the birthday party:

The Transformers themed dessert table in yellow and black

Hope you enjoyed reading this.

Happy Decorating 🙂