Almost none of the dishes listed include the majority of their ingredients - I mean, leek, dandelion and vinegar make a salad, I guess, but not a good one, and I wouldn't want to make parsnip soup as listed. Not a thing made with "wheat flour" doesn't need significant processing and other ingredients (bread, pizza, spaghetti, etc etc etc etc). The salmon dinner mentions lemon spritz in its description but there are no lemons in game. Pepper poppers with no breading, fish tacos with no salsa or cheese, nothing has seasonings, stir fry "on a bed of rice" without rice as an ingredient... not to mention that Evelyn complains that Gus is serving only meat at the festival while if you eat off his grill you get... a survival burger, which has no meat.
my justification is just to mentally assume that the farmer bought kitchen staples (or moved in with them) and has stuff like salt, seasonings and cocoa in their pantry.