Anyway, the M&Ms melted into a gooey mess at the bottom of the pan - underneath the cake! Unfortunately I had not put parchment paper in the bottom of the cake pan so I had to scrape it out of the bottom. It was NOT PRETTY, lol.
So, I tried again only this time with peanut butter chips. I froze the chips first and didn't use the cake strips. AND I put parchment paper on the bottom of the cake pan. The chips stayed in with the batter, but they still drifted to the bottom of the cake. However, I was able to get the cakes out of the pans easily thanks to the parchment paper.
Has anyone done this successfully and how did you do it?