I do have access to the WSJ and there are 12 comments on the recipe, all reporting the same or similar issue. Editing to say that after I re-read the comments, there were a few unrelated to that issue, so most but not all of them had problems.
QuoteVesuvius made a smaller mess in Naples than this made in my oven.
QuoteI used a 10 inch Lodge iron skillet, and after about fifteen minutes in the oven, I started smelling something burning. The batter had risen over the top of the skillet and splattered onto the floor of the oven. I took it out, transferred the batter into a larger pan, and everything came out fine.