Well that was... interesting.
Their guest of this episode was a "Senior VP Global Brand Licensing Manager" at Hasbro by the name of Simon Waters.... someone I've never heard of before, so is either new (this episode was produced late 2016), or someone who isn't involved with Transformers enough to appear at Conventions or Product videos.
The Hasbro guest judge noted that he loved the Autobot symbol on the front of one of the Blurr cakes, but it was not very well done, so maybe he doesn't have much to with Transformers at all to even know what an Autobot symbol actually looks like.
Unless all of these bakers were long time fans of Transformers, I think they must have been given guides on the different series over the years or allowed to do some internet researching, because a number of ideas were a bit obscure (like Animated Blurr and Combiner Wars Leader Megatron) or a mix of different series together on the one cake.
The first round of four teams had to create in 75 minutes, a cake that represented their "all time favourite Transformers character", but I didn't realise Blurr was that popular, as these were the four cakes...
- a mid-transformation Blurr cake (looks like it was based on the GEN-2010 redeco of the first Generations Drift toy)
- an Animated Blurr cake (just the car mode on top and a 2D face on the side of the cake)
- "Gen1" Optimus Prime on top of a round building (Optimus looked more like Softimus Prime, being very rounded and cuddly like a plush toy)
- Gen1 Soundwave breaking out of the street (the person painting it called it Optimus at one point)
The team that did the Animated Blurr cake was eliminated, and the last three teams moved onto round two, which gave them 4 hours to make an "epic battle" themed cake.
- a city battle with Combiner Wars Optimus vs CW Megatron, and a lenticular Autobot/Decepticon symbol on the top.
- layers of several cakes that represent Cybertron to Earth with several characters all over it, from different eras (probably not intentional though).
- a giant Optimus Prime (time ran out before the head was painted, leaving it completely white - this was the same team that did Soundwave in the first round, and it's head was white too).
From that second round, one team was eliminated (the giant Optimus), and the remaining two teams go on (to a final or to the next episode), with the Optimus Vs Megatron cake being announced the winner, earning that team $10,000 and having their cake taken to a party somewhere unknown (briefly shown, with probably only a dozen people and kids - other end of episode parties are usually huge with a hundred plus people).
Various commercials for this "baked month" on SBS had a transforming Optimus truck that looked like a cake, which I thought was from this episode... but it wasn't, and must be from another TV show on this month, or just a clip they pulled from youtube.