Strip the onions of their outermost states and cut them into at least half an inch thick rounds.
Pull the rings apart from each other by applying gentle pressure while avoiding breaking them.
Next, prepare the batter. Put the flour, paprika, and black pepper in a small bowl and mix well.
Pour cold sparkling water in a trickle, and with a whisk, mix well until a smooth batter forms.
In a second bowl, pour the breadcrumbs and season with salt, pepper, and dried parsley.
Dip the rings first in the batter, helping with tongs or a fork, then in the breadcrumb mixture. Make sure to cover the entire onion ring with the breadcrumbs.
Continue in this way until all the rings are finished.
Preheat the air fryer to 350°F for 2 minutes. Using some spray oil or a kitchen brush, spray or brush the base of the air fryer basket, and place the onion rings in a single layer, being careful not to overlap them.
Cook in the air fryer at 370°F (190°C) for 10 minutes or until your preferred golden brown.
Serve this crunchy onion rings hot with a sprinkle of salt and your favorite sauce.