Thin enough to flash-fry but thick enough to let the sweet onion flavor shine through, these onion rings work well as a side dish but also are great as a stand-alone snack. Heat the oil to at least 360 degrees, and fry the rings in batches. They cook so quickly it is easy to get through the frying in 10 minutes. Keep them warm in a 200 degree oven until all the frying is done. (Photo: Amber Fouts for The New York Times)