I've recently switched over to cast-iron skillets for all of my cooking needs.
While my stews taste much, much better, I haven't head any luck getting my omelets and other egg concoctions to do anything but stick to the bottom of the skillets.
I've used the skillets for about a month and have taken proper care of them, drying and coating them with fat after every use. Teflon pans were awesome for eggs, but they're also not so awesome for your health.
Has anyone had much luck cooking eggs/omelets with cast-iron skillets? What are your recommendations?
Use more fat. Most people who switch from teflon to cast iron expect proteins to just slide off the surface with a whisper of veggie oil spray. Try putting a couple tablespoons of butter or coconut oil in the pan before the eggs hit. You'll be amazed at the results.
For me, the answer to avoid eggs stricking to the pan when making omelets, has been to use enough fat, as Moonablaze has said, and to make sure the fat is hot enough before adding the egg(s).
My theory is that the eggs then coagulate in the hot fat and not on the direct surface of the of the skillet.
Fat and preheating yes, I can fry an omelette and it comes out of my cast-iron as if the pan were teflon. However, I don't use my cast irons for anything other than frying, searing, sautéing, or things like oven pancakes where fat is involved but not a lot of liquid at this point. Stew? If your stew has tomato or acidic ingredients, it's going to start working off any good seasoning you have, in my experience. For stew, I'd get an enameled dutch oven or use some other type of pot if possible. I do stews and such in my crockpot usually anyway so I brown or sauté meats and onion in my cast irons but then all the liquids go into the crock. Eons ago I'd do sauces and other things in my cast iron but it always gave me problems with the seasoning.
You must properly season cast iron. Most people think they know how, but actually don't have a clue how much work it is to do it properly.
Put one rack in the oven just above the bottom burner/heating element. Cover in tin foil, with a concave shape towards the middle. Otherwise your smoke alarm will drive you mad.
Scrub the gear with steel wool, removing absolutely everything! If you happen to have a sandblasted, use it. I'm not kidding! remove any wooden handles before doing anything, you can put them back on later.
Get lard. Lots of it. And not that hydrogenated crap. Get the good stuff, Leaf Lard.
Smear a good coating of lard all over all metal surfaces. Place in oven upside down, for two hours at 400 degrees. There wil be smoke. And a lot of it.
Remove the cast iron using a silicone oven mitt (I cannot stress that enough, any fabric will allow liquid through and burn your hand!) let cool enough to handle.
Repeat a minimum of 4 times. You will see a nice, shining black patina after 4 sessions.
To use for the most killer eggs even, use a tablespoon of animal fat (I prefer leaf lard for any cooking application) heat the pan to cooking temperature (for eggs, use medium heat. Any hotter is no good for eggs) then cook as normal. Nothing will stick to your pans now!
To wash, use a soft scrub brush WITHOUT SOAP! Soap will ruin the patina you spent a day creating.
Dry with a paper towel, then smear a thin coating of lard/unsalted butter on the inside of the pan, place on the stovetop burner and hit with high heat till smoke appears. Remove from heat and let cool. I toss it in the oven to contain the smoke. This both restores the patina & gives you a sterile pan to work with next time.
Repeat seasoning yearly, or as you find food sticking more & more.
Nothing will ever stick to your pans ever again.
Take a couple weeks, and do only one thing in your cast iron--sautee veggies in plenty of fat. No eggs, no bacon (bacon is the worst for sticking--so many brands have a bit of sugar in them), no meats, nothing that can stick. You'll get a good season that sticks on there. Then try your eggs again. With, as others have said, plenty of butter.
There are some great videos on YouTube about how to cook eggs in both iron & stainless steel. The pan needs to be pretty hot, as Troels Rasmussen said above. I use stainless but it's a similar routine: start heating the pan while you get your other food item(s) ready, then when it's reasonably hot, add your fat, then add eggs. With stainless, it works best if you then leave the eggs undisturbed until the bottom layer cooks -- I don't know if you need to do that with iron or not.
My cast iron skillets are completely nonstick even for eggs. The pan must be preheated. Then add fat. For me a very light coating of olive oil with a silicone basting brush is all it takes. Literally a drop or two. Let that heat for a few seconds and nothing sticks. After I wash them (no soap) I put the skillets back on the stove and heat them until they are hot and dry. Then I repeat the olive oil step (a light coating is very important) let it heat for a minute and then turn off the heat. I never have to use more than a drop or two of oil with this method.
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