Q: "How should I finish wooden plates/bowls/feast gear?"

A: The modern, durable finish that most woodworkers use for both eating utensils and toys for small children is referred to as "salad bowl finish." It's a food-safe polyurethane finish that cures hard over night, requires very little maintenance, and is generally preferred for re-enactment use, even though it is not medieval. It would be more accurate for our period to use linseed oil, either raw or boiled. Raw linseed oil (or flax oil), is said to take about 2 weeks to cure. I've never seen it cure completely. It always seems to stay a little sticky in my experience. If you boil it first, it cures better, and faster. Again, this is outside my experience. For food-safe applications, I use olive oil. Some folks say it "turns rancid," but that's not been my experience. I rub in multiple coats of olive oil, and immediately rub the item with salt. I just cover it with salt. Then I wipe the salt off with a paper towel moistened with olive oil. This treatment has to be repeated every year or so.