I always thought that the food in Fallout had a lot of character. Not safe, palatable or even edible, but it had character. Some examples I found in the dialogue files. (aside from the staple inventory items like iguana-on-a-stick etc.)
Brahmin Fries
What makes ours taste so special is that you have to harvest it while the brahmin is still alive. You just grab the brahmin by the scrotum and snip four with one cut. You’ve got be careful; the brahmin usually gets riled up at that point. Then you just dip them in batter, add some salt and fry in grease until golden brown.
Canis burgers
Our burgers are made of nothing but the choicest, select, grade-A dog. The meat is ground up and made into half-pound patties. And to give it that unique smoky flavor, they are slow grilled over dried brahmin dung.
Rat Surprise
Catch rat. Careful no squish too much. Hang by tail on wall. Let hang til tail fall off. It ready then. Eat quickly, if let sit too long, the surprise crawl out and fly away.
On the subject of PA food, it would really depend on when the Apocalyptic event that changed the world occured, a reasonably short time after it, people could survive on rations and canned goods and other preserved foods. A long time after... life goes on, and people would turn to whatever hardy livestock or plantlife is available. Also depending on supply, cannibalism would probably have arisen as a way of life.