If I were to over-simplify the problem, Uki and Zeph, is the issue basically "If One Piece had Ratatouille as a dish in the manga, is it based on the actual French cuisine, or did he recently watch that Disney film and decided to draw it? If we don't know, which do we assume?"
Or am I wrong in that assumption.
Because in that case, I would simply assume French cuisine unless there's anything suggesting otherwise.
Like rats being prominently involved.
The way the dish is served is visually unique in the movie to look artsy, so if he drew it like that, it would be the movie. If he drew it like typical ratatouille, it'd be french cuisine.