As I see it my food options are:
1. Just make stuff up. Rename grains, beans, the animals with fantasy versions that do the same job. Frankly, this seems silly. I'm pretty much a full on Gygaxian naturalist; I like things to make sense, or at least follow rules. If I make up an animal, it takes the niche of another animal, or I have to construct a new niche for it. The second sounds like hard work and ends up a bit silly ("The Yakox, a small six-legged horned hairy herbivore spends autumns in the forest eating the nectapples, an apple that tastes like a nectarine and is bright pink.") If it fills the same niche, why change the name? Instead, fantasise it up in the details ("The Norland cattle are long legged with a black and white striped hide.")
2. Just use regular food. In this way I can bring all my cooking knowledge. I don't cook classical or medieval or renaissance style, but you know, faking it is easy, right? Instead of using a food processor, press everything through a sieve, and instead of using a sieve crush everything in a pestle and mortar. Instead of a nice cast iron ceramic pot, use a copper one, or a tin one, or a pottery bowl. Instead of the electric oven, use a cast iron stove, and instead of a stove use a clay oven, and instead of an oven use an open fire. It all comes out the same in the end doesn't it?
As I hope is clear, this is okay if you don't spend too much time in the kitchens. Who cares if your fantasy Romans are using tomatoes and potatoes and chillies and other new world ingredients, and preparing them in ways that would require hours of back breaking labour. If we're in a castle, that's what the servants are for. If we're not in a castle we'll eat stew.
3. Restrict to Old World ingredients, and generally old school cooking. Since I want to maximise writing and minimise research for the first draft, I'm thinking basically North European. So lots of pepper, beef, apples, honey for feasts. Fish and Fowl as well. The rest of the time we're mostly eating porridge with vegetables and some sort of meat broth (because our heroes aren't going to do great deeds if they're half starved all the time). Imported luxuries include citrus fruits and spices. The further north you get the harder it is to make salt, so fat and ice cellars will be used as preservatives.
3a. Fantasy world! So why not have New World ingredients as magical stuff from far away? Chillies and tomatoes as exotic flavours, potatoes as magically nutritious foodstuffs (also bananas). Sounds pretty good.
 Okay is not high praise from me.
 It's always stew. This is because when we're on our world spanning quest to find the Mighty Axe of Kloblock we need food that is light and lasts, which means dried. If we have a cooking pot, then with firewood and a supply of water we can cook our dried meat and beans and make something edible. It's always stew and always will be.
 Or New World ingredients if I fancy a challenge.
 Liking the idea of Elves having their own version of Three Sisters agriculture.