This is in some ways a question we don't have good answers to yet. We know what some people did, but we've only an exceedingly small sample of cookware compared to the number of people who cooked things.

What I can tell you is that cast iron cookware is a fairly late invention, but that riveted iron was used, and that it was prevented from rusting in the same we do today, by covering them in oil and keeping them so, letting the oils build up to a good cooking surface.

Other than that, there are a wide, wide variety of cookwares known.

At the very basic level, you have the option of putting your food on a stick and holding it near the fire until it's cooked. This is formalised as a roasting spit, put on a rack in front of a fire and turned regularly, which was a method used in kitchens up until the 18th century. Indeed, the modern rotisserie is the latest evolution of this.

Then there's the method used in pre-Norman Ireland, the fulacht fiadh, which is a stone or wood-lined pit, filled with water, into which your food is placed along with hot stones direct from a fire, which make the water boil. It's possible they also boiled stuff in leather bags over fires, although this hasn't been conclusively shown.

And you can wrap your food well in leaves and and bury it in the coals, in the same way as we bake potatoes in tinfoil in campfires now.

Next, there are stoneware cooking pots, made for the most part from soapstone, which can be carved easily, and takes heat well. This was widely used in the Middle East, and is still used in Brazil, among other places. Sometimes they're bound with copper rings to make sure they don't split.

Earthenware pots are also used, and these were probably, item for item, the most widely used over the era you're looking for. They handle heat well, and you as long as they're stirred, you can cook something in them for a long time fairly safely - they hold heat better than metal pots do, so the vagaries of wood fires are evened out a bit. There are a lot of singed potshards in medieval archaeological findings, so this is pretty well supported.

Metals pots in the form of riveted copper or iron were also present - they would have been expensive, and would usually have been fairly large - more cauldron than pot, in our terms. Metal frying pans don't seem to have been common; frying was either done in large flat earthenware pots or just not done at all.