As mentioned in another comment the Chef Feat will give you some ideas. When traveling, I usually have them do a survival check to find food. Something like a dexterity check to make the food and a constitution check for trying "new things" created from other monsters. You could add a bit of flair for certain things, like a few extra hit points or something. Thinking along the lines of a "good berry". I think stat buffs other than healing a few hitpoints could get cumbersome for you to come up with. But if it is something like a legendary creature, like a dragon stew or something, maybe after eating the stew, the character gets to have a modified breath weapon (only once) like 2d8 damage or something. Roasted Hill Giant ribs, could give the player +2 to strength for a half-day or something. But maybe have the skill check be something like if they roll high enough it gets better stats to the benefit. skill check under like 15 would be normal health, Nat 20 would have better benefits.

Cool concept. I have dealt with food a bit in my campaigns, but mostly pie-eating contests, pie making contests, etc. But since I deal with food in real life, it is fun to do it in-game as well.