Aren't prose recipes a kind of program source-code; and aren't the underlying ideas of their steps, algorithms? The law says you can copyright source code, but not a program's underlying algorithmic semantics[1].
What I'm talking about here, is effectively "extracting the semantics of someone else's source code/recipe, in a way where humans are "firewalled off" from the particulars of the original prose of the code/recipe; and then using the described semantics to write your own code/recipe that has those same semantics."
This is explicitly something that's been decided as not copyright-infringing; which is why IP lawyers have to go after cases where there was literal plagiarism of source code, however small.
The big example of this is Google v. Oracle, where API header files used in Android were literally plagiarized from OpenJDK. Google argued that this was fair use, as there was essentially no other form these files could take while retaining Java compatibility. But this argument was shut down/never resolved in their favor.
All Google had to do, in the end, to avoid infringement, was to do a ground-up rewrite of those Android API header files (which ended up almost exactly the same as they were before the rewrite.) Note that they still rewrote them using an understanding of the bare facts that those header files contain, that could only have been gained by reading the original header files themselves. And yet the new derivative work, being "not literally plagiarism", was no longer considered an infringing derivative work.
[1] You can patent algorithms (sort of, as business processes), but that's a different thing. Nobody's ever going to sue a recipe website for patent infringement, even if they described Nestle's patented chocolate-enrobing technique, because a description of a patented process is not a use of that patent. Patents are inherently public information, and people can share and reprint the information in them around all they like. Instead, a patent owner would only sue other companies who used the patented technique for commercial gain, for not first acquiring a license for the patented technique. (Google never sued bloggers for describing the PageRank algorithm; but up until last year, Google did sue other search-engine companies for implementing PageRank without a license.)