You may be trying to say that something is as hot as a ''coal,'' a ''hot coal,'' or ''charcoal'' but those aren't expressions we use in American English to describe food. It would be confusing to most people. There are many other ways to describe really hot food that all would work. Here are a few:
That food is boiling hot (like Hilary Metcalf says in the other comment)
This food is scalding hot
This food is on fire
This is like lava
and on and on ...
Hopefully that helps a little bit!