Ingredients
2 sweet onions, peeled and sliced into 1/2-inch-thick rounds (or half moons)
3 cups beer
2 teaspoons vinegar (I used red apple balsamic vinegar.  Cider vinegar or malt vinegar would work well.)
Salt and pepper
2 quarts peanut or vegetable oil
3/4 cup all purpose flour
3/4 cup cornstarch
1 teaspoon baking powder

Instructions
1. Place onion rounds, 2 cups beer, vinegar, 1/2 teaspoon salt, and 1/2 teaspoon pepper in zip-top bag; refrigerate 30 minutes or up to 2 hours.

2. Heat oil in large Dutch oven over medium-high heat to 350*F. While oil is heating, combine flour, cornstarch, baking powder, 1/2 teaspoon salt, and 1/4 teaspoon pepper in large bowl. Slowly whisk in 3/4 cup beer until just combined (some lumps will remain). Whisk in remaining beer as needed, 1 tablespoon at a time, until batter falls from whisk in steady stream and leaves faint trail across surface of batter.

3. Adjust oven rack to middle position and heat oven to 200*F. Remove onions from refrigerator and pour off liquid. Pat onions rounds dry with paper towels and separate into rings. Transfer one third of rings to batter. One at a time, carefully transfer battered rings to oil. (Tongs work well for this.)  Fry until rings are golden brown and crisp, about 5 minutes, flipping halfway through frying. Drain rings on paper towel-lined baking sheet, season with salt and pepper, and transfer to oven. Return oil to 350*F and repeat with remaining onion rings and batter. Serve. 



Comments
This recipe is from the 2009 Cook's Country Annual and the onions were delicious.  I cut the slices into half moons, because I think they’re easier to deal with.  I also tossed the little onion bits from the center of the onions with the remaining batter at the end and dropped them into the oil in spoon-sized clumps.  The onion batter was nice and crisp, even at the end of all the frying.  The onions were soft and scrumptious.  We ate them with a variety of sauces – my favorite being honey, mustard and mayonnaise all mixed together.