Pre-heat the air fryer to 350°F.
Cut the onion in half, leaving the root end intact; cut each half into 3 wedges, then cut the root end off; separate each wedge into petals; set aside.
In a small bowl, beat the egg and milk.
In a large resealable bag, combine the flour, salt, pepper, cayenne pepper, paprika, garlic powder, onion powder and baking powder.
Add the onions to the bag, seal and shake to coat.
Shake off the excess flour and transfer the petals to the egg mixture.
Return to the flour mixture and shake to coat.
Place the petals in the air fryer.
Generously coat the onions with non-stick cooking oil; there should be no visible dry flour.
Cook for 5 minutes; flip the petals; spray with oil again to ensure there is no dry flour; return to air fryer and cook for another 5 minutes.
Finally, flip the onions once more and cook for 5 minutes.
Serve with sauce.
