Covering onions in buttermilk for at least 30 minutes removes their pungent bite, leaving you with sweet, tender onion rings in a crisp beer-battered shell.
Source: Everyday Food, April 2011
Yield Makes 2 1/2 cups batter
2 large eggs
1 bottle light- or medium-bodied lager (12 ounces), cold
2 1/2 cups all-purpose flour (spooned and leveled)
5 cups vegetable oil
2 1/2 to 3 pounds shrimp, firm fish fillets (such as cod), or desired vegetables (such as onions or pepperoncini), cut into pieces if necessary
2 cups buttermilk (if using onions)
In a medium bowl, whisk eggs until smooth, then whisk in beer. Add 1 1/2 cups flour and 1 1/2 teaspoons salt and whisk until combined. Place 1 cup flour in a shallow bowl. Place a wire rack on top of a rimmed baking sheet; set near stove.
In a wide 6-quart pot fitted with a deep-fat or candy thermometer, heat oil to 375 degrees over medium. (The oil should bubble rapidly when a pinch of flour is added.) Working in small batches, lightly coat food in flour, then dip in batter, gently shaking off excess. Fry, turning halfway through, until browned and crisp, about 5 minutes per batch (adjust heat to maintain 375 degrees). With a slotted spoon, transfer food to rack to drain and discard any browned bits of batter. Season immediately with salt. Keep warm in a 200-degree oven.