Peel the onion and slice it into 12-16 thin petals, stopping about 1/2 inch from the bottom so the onion stays whole.
In a bowl, combine flour, paprika, garlic powder, salt, and black pepper.
In a separate bowl, whisk together eggs and milk until smooth.
Coat the onion petals first in the flour mixture, making sure to gently separate the petals as you coat.
Dip the floured onion into the egg mixture, then carefully dredge in the bread crumbs, making sure to get between each petal.
Shake off excess and place the coated onion in the air fryer basket, cut side down.
Air fry at 375°F (190°C) for 12-15 minutes, or until golden and crispy. Check halfway through cooking and gently flip if needed for even crisping.
While the onion cooks, mix mayonnaise, sour cream, ketchup, garlic powder, paprika, and salt in a small bowl to create the dipping sauce.
Once the bloomin' onion is crispy and cooked through, carefully transfer to a serving plate and serve warm with the tangy garlic dipping sauce.