Electric frying pan, 1970s, with cover. theterrifictc / wikimedia / 2008 / CC BY-SA 2.0
Electric frying pans are frying pans whose heat source comes from an electrical element attached to them. They are not designed for stove-top use.
They tend to be square. Almost all come with a thermostat to regulate the heat that you take off when you wash the pans.
Older ones had hot and cold spots, because the heating element was just a ring under the bottom.
Some come with high-domed lids so that you can do roasting or baking in them. For baking, put a metal trivet in them, and then your baking pan on top of that.
Lids usually have a vent in them that you can open to let steam out.
Some come with ceramic inserts, letting them act somewhat like a slow-cooker.
Electric frying pan, 1970s, with ceramic insert. © Ian Graham / 2011
Electric frying pans are good for simmering and slow cooking, both being cooking methods that allow unattended cooking (for short times, for obvious safety reasons.) Electric frying pans will maintain a controlled temperature during this time. They can also be used for braising, stewing, and some oven-type dishes. You can make spaghetti sauce and fried chicken in them.
Electric frying pans are also a popular table tool at parties for keeping food such as Swedish meatballs warm.