This was something I've been meaning to try for over a year. I never would have thought of it except for a fellow highschool classmate - Heather - who I have found on Facebook, who is an extremely talented cake decorator, had done something similar for her class and had posted a picture. I couldn't find anything about an "impossible" cake online but eventually came across something famous in London called the Puzzle cake which looked similar, but a little more frumpy than Heather's.
There were directions for this frumpy Puzzle cake but I didn't quite like them and it didn't match up with Heather's 100% so I decided to make a game out of it and visualize and sketch out how this possibly was done. The "impossible" part is that when you take a slice of this supposedly normal looking cake, there is a section of cake layers that are going in totally different direction as the normal horizontal cake layers. Normal people don't really think much about this but for some one who bakes cakes, this is quite the puzzle as to how this is done.
The main idea was to make an alternating layered cake and then cut out a triangular ring, as close to an equilateral triangle as possible, and then rotate the ring and put it back on the cake, covering it with your last reserved layer.
This didn't quite go as smoothly as I had envisioned, I imagine in pastry chef school and as well as the Puzzle Cake description I saw online that, this should be done with stretchy sponge cake and not tender, moise box cake. However, I don't really like sponge cake that much so what was the point of something that looked cool but tasted like mushy nothingness? Box cake it was, and since the cake was for a family member's birthday, at least my audience would understand.
When I flipped the tubular triangle wedge upside down and back on the cake, the box cake totally crumbled off in some places and it looked like a total mess. I didn't even take a picture because I was thinking "well I guess I can just... bake a new cake real quick." But, something told me to just try and patch all of the sorry pieces back together with more frosting. By golly, it actually seemed to stay put and I quickly covered this piecemeal mangled layer with the last reserved layer of cake. With one final chocolate frosting coating all over the cake, it actually looked like a normal cake. I couldn't believe it!
I was hoping that even though I knew there were broken shards of cake in there, that we would still see the cool diagonal layer inside of a slice of cake, and that it didn't crumble as soon as I sliced it. Unfortunately I wouldn't be able to find out until after dinner and it was time to serve the cake to Chris!
I couldn't believe my eyes when I took the first slice of cake - it had worked! I was very excited. If I were to do this again, I would make the section opposite cake layers even larger so that it was more pronounced. I used a new chocolate frosting recipe from Martha but since it turned out sorta lumpy, I'm not going to mention which one. Hope you had a happy birthday Chris!