, cut in 1/8-in. rounds, separated into rings
BOIL a kettle of water. Pour boiling water over onion rings in a large bowl until covered. Let stand 2 min, then drain.
BOIL vinegar with sugar, salt and garlic in a medium saucepan until sugar dissolves. Remove from heat and add onion rings. Press onion into liquid and let stand for at least 30 min. Use right away or refrigerate up to 1 week.