You probably don't want to know you can make better-than-restaurant quality onion rings in your own kitchen, but these are the best onion rings I've ever had. The recipe is from Cook's Country June/July 2009 from America's Test Kitchens. Make sure you don't soak the onion rounds longer than 2 hours or they will turn soft and become too saturated to crisp properly. Cider vinegar may be used in place of malt vinegar. Use a candy thermometer to make sure the oil gets to 350 degrees. According to Cook's Country, ordinary yellow onions will produce acceptable rings but sweet onions are preferred. The beer soaking with vinegar and salt softens and flavors the raw onion. If the batter is too thick, the rings will be doughy. Too thin, and it will run off. Add the beer gradually until the batter falls from the whisk to form a ribbon trail. Fry the battered onion rings in small batches and transfer them one at a time to the hot oil so they don't stick together.