By “name of a prepared food” as per the subject, I mean:
a) something with a recipe that produces a finished item, rather than just a food term (“vino” for “wine”),
b) isn’t just a descriptive process and name (“fried X” or “cooked Y”, etc.),
c) that is known to have been around back in the in Year Whatever, such that
d) if you teleported someone from that era to the present day, dropped a plate of the stuff in front of him/her, and said “have some X” using the modern day term, their reaction would be “OK” instead of “what are you talking about?” or “how is THIS what you call X?”.
In this context a location based name would count, but would have to have retained the exact same meaning going back N years for my reckoning.
So for example, the term “fan4” (traditional Chinese/Han character of “飯”) has been used for cooked rice for millenia, and “炒飯” (“fried rice”) surely has been eaten for nearly as long; but a specific and very common dish of Yangzhou Fried Rice (“揚州炒飯”) has a documented history that only goes back to the late 18th Century, even though surely they were eating some kind of fried rice in Yangzhou, China well before that.
The best example I can think of so far is the widespread use of a derivative of the Latin name for a kind of primarily pork sausage eaten during Ancient Roman times, “lucanica”, with mention as far back 2,000 years in the Roman cookbook of Apicius. This name has continued to the present day with recognizable cognates in former Roman Empire territories such as the modern Italian “luganega”, Greek “loukaniko”, Portuguese “linguiça”, Spanish “longaniza”, Bulgarian “lukanka”, and even Arabic “laqāniq”.
They are all somewhat different in recipe from each other, and some include more than just pork, but they’re all some form of smoked and spiced sausage where I am pretty sure if you dropped one in front of Cicero and identified it by its spoken local name, he’d both understand and agree with the name for what he was eating. Although maybe with a remark along the lines of a “Chicago versus New York Pizza” type of thing.
Any more like that? “Pizza” has ancient roots as a word, related to modern day “pita” for flat, leavened bread, but I think our modern version of what “pizza” is (baked with cheese, garlic, usually sauce, etc., on top) would be unrecognizable to the ancients.
Not a simple food term like “cooked rice”, or “bread”, but something like “Challah bread” would count. How old is that term and has it been consistently the same thing?