One of the first cast iron skillets I ever owned was this tiny skillet that I use to cook single eggs.
Amusingly, this skillet was actually being sold to be used as an ashtray. Hence the little pouring spouts on the sides are actually cigarette rests. It works perfectly for my needs though:
Round egg for a round sandwich, perfectly cooked and perfectly released every time.
A seasoned, preheated skillet will easily fry an egg leaving nothing stuck behind. After this pan cooled a bit I wiped it out with a damp towel, spreading a bit of the leftover oil all over it and then put it back away for next time.
I haven’t ever mentioned this here before, but if I had to choose to eat ONE FOOD and only that one thing for the rest of my life, it would be eggs.