Cast iron cookware has been used for centuries, and with some justification. Cast iron cookware is an extremely versatile and economic alternative to expensive copper and copper clad cookware. If you aren't currently using at least a couple of cast iron pans in your kitchen then you should seriously consider it.
But why cast iron? Some people avoid cast iron because it sounds 'old fashioned'. In fact, cast iron is ideally suited to all modern cooking methods and hobs. Cast iron cookware have excellent heat conduction and retention, which means that you get even heating over the entire surface of the pan — ideal for frying. As long as there are no wooden handles you can directly move cast iron cookware from the hob into the oven or under the grill. Ideal for finishing dishes in the oven (great for game) or for browning under the grill.
A properly seasoned cast iron pan, surprisingly is just as non stick as any fancy non-stick pans and cast iron is extremely durable. I have a Victorian skillet that had been handed down in the family for over four generations. Cast iron cookware is much less expensive than copper cookware.
This thing called 'seasoning' is one of the reasons that many people shie away from cast iron. It sounds complicated and they are afraid they cannot do it. In fact, it's an extremely simple process. Most people get it wrong because they use completely the wrong oil. Animal fats won't work, and most vegetable oils won't work either. What you need is flaxseed oil (the food-grade equivalent of linseed oil).
Most people do not understand the chemistry of seasoning and they think that good food-grade oil that does not go rancid is what's needed. But seasoning is not cooking. You have to turn your thinking on its head. Oils with high levels of omega-three fatty acids (especially alpha-linolenic acids) go rancid because the omega-three fatty acids easily oxidize and break down. In seasoning you are trying to give your pan a hard non-stick surface. To achieve this you actually need the oil to bond to the pan. The oil can only bond if it has components that oxidize and fuse with the iron. So you need oils high in omega-three fatty acids. Oils, in other words, that will not normally keep.
Iron itself is very reactive and as long as the surface of your pan is clean and rust free when you heat iron it becomes reactive. When you add the oil, as long as it's just beyond its smoke point the iron will react with the oil and bond to it. This produces the crosslinking you need and the oil coats the surface, making it non-stick.
Wash the pan and strip it down to bare iron if not new. Wash again then heat in an oven pre-heated to 100ºC to ensure it's dry. Carefully take the hot pan from the oven and set on a wire rack. Pour in some flaxseed oil then rub the oil all over the pan with your hands and fingers, making sure that you get into every nook and cranny (by the end your hands and the pan should be very oily.
Now take a piece of kitchen paper and rub off all the oil. Yes, you read that correctly, rub off all the oil, until the pan looks dry. Don't worry, you still have an even coating of oil on the surface of the pan (it's just very thin). If you have done this correctly, the pan should look completely dry.
Set a rack in the middle of a cold oven. Place the pan, upside down on top of this. Turn the oven up as far as it will go and allow the oven to reach temperature. As soon as the oven is hot, time exactly one hour. When the hour is up, turn the oven up. Now, without opening the door allow the oven to cool naturally until it reaches room temperature.
When the pan emerges from the oven, if all is well, it should look a little darker than when it went in and be matte in texture. Just remember that this was only the first coat. Typically the pan needs six coats. Allow to cool completely then repeat the process above for he next coat. Repeat this six times in all. By the time you apply the final coat the pan should have a semi-gloss sheen to it. It is now ready for use.
If you use the pan regularly you need to re-season every six weeks or so.
Of course, cast iron pans are very heavy, but this can be advantageous (try using one to flatten out meat!).
Once you have properly seasoned your cast iron pan you should never use soap or detergent on them, as this will strip off the coating. To clean them, just use hot water and a plastic scouring pad, don't use steel wool, or it could ruin the seasoning (if this happens, just re-season the pan). After washing, dry the pan throughly with lint free paper towels. Store the pans with the lid off to prevent moisture from building up and causing the pan to rust.
Iron is a reactive metal, so you should not use cast iron pans to cook acidic foods, cast iron is a reactive metal, and will react with the acids. Never use your cast iron pans to store food; You can use them to keep food warm during a meal, but when the meal is over, move the food into proper storage containers, and wash your pan.
If you want the benefits of cast iron without the problems of seasoning and not being able to cook some foods in it, then I would suggest Le Creuset cookware. They are made from cast iron, but have enamelling on the inside. You can use them to cook any kind of food you like.
I really love Le Creuset cookware, particularly their Casserole/Cocotte/French Oven styles. The abilities to move them directly from the hob to the oven makes them so versatile. You can also use them to cook accompaniments, stews, curries and even baked puddings.