Step 5: Testing the fit
This was the time make of break point for me. I placed the cake on a 12 x 12 cake board. These are so worth it. $4 for 4. They are high density cardboard so they are as strong as a plate, completely flat, and disposable. I cut out one quarter of the cake, thus a 4x4 piece. I picked it up and placed it on the remaining corner of the cake. This was going to be my brick part of the cake, and it actually fit.
Next I warmed up the large knife with hot water, then cut out a 4x4 chuck of the Jello from the cake pan. I then placed it into the space I had just made in the cake and, to my relief, it fit. I took it back out and placed it aside for now till I decorate the cake. You can smooth the Jello by heating up the blade of the knife with hot water and placing it up against the side of the Jello. This melts the Jello, so be careful not to melt too much.