And my immediate thought was, of course, "Boy, I bet a DRAGON WING would be pretty good in buffalo sauce. Not that I would, um, say that to the Dragon."
They are poisonous and acidic in my game, so it would be like trying to eat Alien.
But ... how do people generally view cuisine in their campaigns? How do they view gastronomy?
As a teenager I was fascinated with cuisine as an aspect of world building, and in particular one account about the Tekumel campaign how the GM was able to answer questions about what people in a typical culture could eat for breakfast (and it was both believable and original) really blew my mind.
I spent a lot of time thinking about menus at taverns and cuisines after that, but over the years I've come to realize that players mostly don't care and that when you are playing with a larger group, you don't really have time to devote to those gritty slice of life matters. Cuisine occasionally comes up in my games - there have been several important meals that occurred where the cuisine mattered in game to some degree and out of game (at least to me) a lot. But I don't spend nearly as much time worrying about it as I did at 17.
1. Do you have fine dining and "restaurants" that the PCs can go to?
Yes, though most fine dining occurs in homes and to have fine dining at a restaurant is a novelty unique to certain large cosmopolitan cities. The idea of going out to eat is novel and largely unknown through most of the world, and most tavern fare is typically for travelers or working class people who need midday meals away from home. Thus, it's much more like what we'd think of now as street food than fine dining, and in particular much of my take on what dining is like is influenced by the road side stands and rum bars of my youth growing up in the Carribean.
Do you have regional cuisines, or different cuisine mapped out by races?
Yes.
As a general rule, do people eat the same things we do (agriculture, domesticated livestock)...
Yes, although as a general rule, cuisine is not as limited as it tends to be in our high population density post-industrialized farm economy where everything is commoditized. However it is certainly an agrarian economy and 'bush meat' is not a typical food source or sustainable even at the population densities present in the less advanced society.
or more fantastical things? How does a Roc taste?
Probably a lot like hawk or eagle, though really, few if any people would ever know. For the most part, eating fantastical things would strike most cultures as highly decadent and probably gluttonous. Most cultures would frown upon it. Of courses there are some notably decadent cultures where something like Roman palace cuisine with its exotic meats, over prepared dishes, and conspicuous excess are more normal. And likewise there are poorer less civilized (in the literal sense) cultures where you eat what you can get and are happy about it.
Is there a prohibition (at least, among good races) to eating "intelligent" creatures? Would people partake in Red Dragon Brisket?
Red dragon flesh being consumed would strike people as relatively weird, and eating any part of its toxic acidic flesh safely requires extensive knowledge of cooking. Roast dragon heart is the sort of thing a palace chef could do and might do to celebrate the triumph, but it's not something most people would even think to do. The intelligence of the dragon wouldn't really be in the first few things that they think about. I mean, forget dragons, any educated person knows that radishes, kale and maize are intelligent or at least can be intelligent, and the culture's experience of "intelligent" is entirely different than our own were we tend to think of ourselves as the solely intelligent thing and define intelligence as an emergent quality (that appears right around our level) and not a spectrum.
Certainly the other free peoples mostly abhor the fact that goblins freely eat other free peoples, and most free peoples who are of the opinion that goblins are no longer free people would site their relish of flesh as one of the proofs of that. And certainly, most good peoples and beings abhor the idea of killing and eating other good peoples and beings, but mostly because it involves killing and acquiring a taste for the flesh of good beings would involve killing.
But, even a farmer asks permission of the garden before he harvests it, and promises to not waste it's bounty and to replant it and to honor and be grateful for it when his family consumes it. So this idea you have is at odds with the world the people live in.
What about "field rations?" Do PCs in your campaign ever prepare creatures they have vanquished? What, if any, are the moral lines?
Sure. If the creature tends to remind the players of some real world food (or is a real world food), then the players tend to be, "Hey, lets eat this for dinner." Giant crabs, dinosaurs, crocodiles, etc. tend to end up on the menu.
Finally, are you still a vegan if you eat a vegepygmy? Vegetarian?
Sure, but in a world where trees, carrots, and even grass is obviously intelligent, is that really even an important question?
UPDATE: I managed to quickly find my notes on the last 'important meal' eaten in my campaign. The menu was:
Smoked Oysters and Fern Fronds
Caterpillars and scallions stir fried in coconut oil
Roasted Yam and Breadfruit
Barbequed fish with scallions and roasted peppers
Baked octopus with carrot and young taro greens
Roasted lemur
Taro pudding, salted smoked fish and sea algae
Raw sugarcane