This is something that should be mentioned somewhere in the documentation and/or item description - I thought I was going INSANE, since I (correctly) thought that you can't cast iron.
Google didn't work, so I chalked it up to poorly documented mechanic and tried a million operations with the bloomery, crucible and bits.
When that didn't work, I went over to the source code of the Expanded Foods and started digging through it, and when that didn't work and I realized it's part of the parent mod, I went through the Culinary Artillery repo.
I couldn't find any evidence that it is actually cast from iron somehow, so I combed through this thread page by page, expecting to see this question at least a dozen times.
And now I see this.
Oh well, at least I know the answer now and can point all of my confused friends to this thread.
TL;DR: Please add important information - the inability to obtain cauldron without a trader - to the item description, otherwise people will waste days searching "how to cast iron in vintage story".
Edit 2 mins later: Note that I am not running the latest version, but one before it - if it was already added then sorry, my bad, but if not please do add it.
