Have you ever wanted to craft an ore, but you couldn't? This is a simple solution for your problem! Add this plugin into your /plugins/ folder and either restart or reload the server (reloading isn't recommended, since it might break other plugins until you restart the server).
This plugin is very lightweight, so you won't suffer from not having enough space for this. Also this is one of the first (or the first) plugin to do this on 1.17.
In the future I'll add support for other versions, right now my goal is 1.17.

Screenshots:



I will consider changing the recipe in the future (swapping ingots and cobblestone), and possibly making it configurable.