I was thinking of breaking things down something like this:
"Simple ingredient": things like raw veggies, meat, or fruit, flour, tallow, seedcakes, etc. Raw food stuffs.
"Condiment": a compound ingredient made of 2 or more simple ingredient. Mayonase, ketchup, pie fillings, gravy, scalded milk, etc.
"Entree'": a single prepared food item, made from any combination of the above two items. Things like "pie", "salad", "sandwich", etc. Each has a specific set of requirements. (Pie needs flour, fat, salt, and a condiment. Yes, that means mayonase pie is allowed. Eat up.) These should be categorised by the number of reagents each needs. Some, like bread, just need flour and water. Others will need 3 ingredients, and some even more than that.
And of course,
"Meal": a finished presentation of at least 2 entrees, or an entree and a simple food.
Eg,
"meager meal", is an entree and a simple food. (Meat and potatoes type meals, or bread and cheese.)
"Common meal" is 2 entrees
"Filling meal" is 3 entrees (or at least 1 entree and an any suitable number of simple food), and
"Lavish meal" is at least 4 entrees (or at least 2 entrees and any number of simple foods.)
Dwarves should be able to consume any of the following, with a few exceptions:
Simple raw food (except inedible things, like raw seeds or straight tallow/butter)
Entree
Meal
Condiments should get [edible_cooked], so that they are still treated as food, but not directly consumed.
Meals would have the greatest possible degree of WTF going on, and also the highest values, being possibly made of many compound ingredients.
You could very well have a lavish meal made of prepared fly brain pie (made of pie crust made from crundle tallow, whipvine flour, and ground salt) filled with prepaired fly brain filling (made from prepared fly brains, and longland flour) served with roasted chicken (chicken meat, served with poultry stuffing (bread made from dwarven flour, mixed with plump helmet wine), mashed bloated tubers (bloated tuber, butter/gravy, salt) and and sunberry shortcake (made from blue peafowl eggs, whip flour, dwarven sugar, horse tallow-- and a filling/topping made from dwarven sugar, sunberries, and sunshine.)
Naturally, such a meal would be quite expensive, AND labor intensive.
It's also almost garanteed to give a dwarf a good thought, because it has basically everything inside it.
(Note, you could also have a gravy flavored cake, or a mayonaise pie, or roasted crundle drizzled in prickleberry sauce.... the permutations of the meal would be extreme.)
I'd have to add a job to convert rock salt boulders into cooking salt at mills/querns, and some jobs to turn raw quarry bush leaves into quarry bush spice, but that's just loose ends.
Perhaps a workshop to turn saltwater into seasalt boulders as well, in the event that rock salt isn't obtainable either locally or by trade. That would give a useful purpose to having a saline aquifer as an added bonus.