One would think, but apparently some EU rule that overrides[1], thanks to our EEA membership[2]. Managed to dig up the article I read back when it was posted, but I've heard from others in the business just a couple of years ago they're still doing it.
edit: Oh and I realize I was having a brainfart, so "modified" should have been "processed". One of those words that can map to multiple English words.
Ah that's a very different thing from your original comment. It's not a raw carcass being brought into Norway; it's ham. (Yes, this distinction matters. Ham is pork which has already been salted.)
Sending ham back to Spain for further curing and mechanical processing would just be considered processing under EU customs rules since it gets sent out as ham...and comes back as ham.
Fair point, I went off what I was told from someone on the inside a decade or so ago, and I distinctly recall them referring to importing a pig and not ham.
Then I recalled the article I had read some years later and managed to dig it up.
Still, a creative trick to avoid tariffs, if wasteful.
edit: Oh and I realize I was having a brainfart, so "modified" should have been "processed". One of those words that can map to multiple English words.
[1]: https://www.nrk.no/norge/ellevill-skinkereise-1.11613122
[2]: https://en.wikipedia.org/wiki/European_Economic_Area