I love having onion rings with my burgers and steaks, but they're sometimes more trouble than what it's worth... there's the slicing and the batter and the breading, not to mention dragging out the deep fryer and then having to clean it all up when you're done.
So I cheat. I buy huge bags of frozen onion rings at Sam's Club. When I want onion rings, I remove them from the freezer about 90 minutes ahead of time, use the sharp edge of a knife to knock all of the ice crystals off and lay them in a single layer on a rack to thaw.
About 15 minutes before dinner time, I spray them with a good coat of cooking spray and shove the rack into an oven preheated to 400 degrees Fahrenheit for about 12 minutes until they're golden brown.
They're not as good as home-made and deep-fried, but they're good 'nuf.