01 - Separate the sliced onions into individual rings and pat dry with paper towels.
02 - In a large bowl, combine all-purpose flour, cornstarch, salt, black pepper, and optional paprika.
03 - Toss onion rings in the flour mixture until evenly coated, then shake off excess.
04 - Heat vegetable oil in a deep skillet or saucepan to 350°F (175°C).
05 - Fry the coated onions in batches, stirring occasionally, until golden brown and crispy, about 2 to 3 minutes per batch.
06 - Remove onions with a slotted spoon and drain on paper towels. Let them cool slightly before serving or using as a topping.