Seltzer water is the secret to achieving a delicate crust on homemade onion rings. Use a deep-fry thermometer to monitor the oil, and be sure to maintain a temperature of 375 degrees; otherwise, the rings will absorb too much oil as they cook.

　　

Ingredients

serves 4

　　1 large sweet onion, such as Vidalia, sliced crosswise into thin rings

　　1 1/4 cups all-purpose flour

　　1/2 cup cornstarch

　　1 1/2 teaspoons baking powder

　　Coarse salt

　　12 ounces seltzer water (1 1/2 cups)

　　6 cups vegetable oil, such as safflower

　　1/2 cup packed fresh flat-leaf parsley leaves

　　

Step 1

Preheat oven to 250°F. Soak onion slices in a large bowl of ice water 10 minutes; drain and pat dry with paper towels. In a large bowl, whisk together flour, cornstarch, baking powder, 1 teaspoon salt, and seltzer.

　　

Step 2

In a large heavy pot, heat oil over high until a deep-fry (or candy) thermometer registers 375°F. Working in seven or eight batches, place onion in batter, coating completely; using your fingers, lift out, letting excess drip back into bowl. Carefully lower onion slices into oil, making sure not to overcrowd pot; cook until golden brown, 2 to 3 minutes.

　　

Step 3

Use a spider—a wide and shallow wire skimmer—or a big slotted spoon to transfer onion rings to a paper towel-lined baking sheet, and season with salt. Keep warm in the oven. Return cooking oil to 375°F before coating more onion with batter and frying.

　　

Step 4

After the last batch is cooked, place onion rings on a platter. Carefully lower parsley into pot (oil will spatter), and fry until crisp, about 10 seconds; transfer to baking sheet with a spider or slotted spoon, and season with salt. Sprinkle parsley over the onion rings, and serve immediately.

　　Everyday Food: Fresh Flavor Fast by Martha Stewart Living Magazine. Copyright © 2010 by Martha Stewart Living Magazine. Published by the Crown Publishing Group. All Rights Reserved.Martha Stewart Living magazine was first published in 1990. Over the years, more than two dozen books have been published by the magazine’s editors.Martha Stewart is the author of dozens of best-selling books on cooking, entertaining, gardening, weddings, and decorating. She is the host of The Martha Stewart Show, the successful daily syndicated television show.