-
1
Preheat oven to 250F.
-
2
Soak onion slices in a large bowl of ice water 10 minutes; drain and pat dry with paper towels.
-
3
In a large bowl, whisk together flour, cornstarch, baking powder, 1 teaspoon salt, and seltzer.
-
4
In a large heavy pot, heat oil over high until a deep-fry (or candy) thermometer registers 375F.
-
5
Working in seven or eight batches, place onion in batter, coating completely; using your fingers, lift out, letting excess drip back into bowl.
-
6
Carefully lower onion slices into oil, making sure not to overcrowd pot; cook until golden brown, 2 to 3 minutes.
-
7
Use a spidera wide and shallow wire skimmeror a big slotted spoon to transfer onion rings to a paper towel-lined baking sheet, and season with salt.
-
8
Keep warm in the oven.
-
9
Return cooking oil to 375F before coating more onion with batter and frying.
-
10
After the last batch is cooked, place onion rings on a platter.
-
11
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.
-
12
Sprinkle parsley over the onion rings, and serve immediately.
