Plastic Man #2 (1944) is a treasure of the Golden Age. The Grand Comics Database credits Jack Cole as authoring, pencilling and inking the 56 pages. I don’t know if he did it strictly solo, but he signed the stories.
I am also willing to guess this was a best seller in its day. I have picked the tale of the hypnotist and a whole town under his mad spell. For me it is Jack Cole at his wacky best.