A little note here - one fairly large onion goes a long way.
Fry them up in peanut or canola oil until they turn golden brown. Only flip them once and try not to move them around too much so the coating doesn't fall off in the oil. Drain the rings on a platter lined with paper towels. Salt and pepper to taste as soon as they hit the platter.
A simple side to onion rings would be a big, thick, juicy burger. Believe it or not, but this is a fairly low fat burger.