Trim a thin slice from the root end of each onion so it sits flat, slice off the top, and peel away the outer skin, keeping the root intact so the mini blooming onions hold together.

Place an onion root side down and make 4 cuts from near the root to the top, then add more cuts between those sections to create multiple petals, gently separating them with your fingers so the onion can bloom.

In a shallow bowl, whisk together the flour, cornstarch, smoked paprika, garlic powder, onion powder, salt, pepper, and cayenne until well combined.

In a second bowl, whisk the eggs and buttermilk until smooth to create the wet batter.

Dust each prepared onion in the seasoned flour mixture, shaking gently so the flour falls between the petals and coats as much surface as possible.

Dip the floured onions into the egg mixture, let the excess drip off, then return them to the flour mixture and press to form a thick, even coating.

Preheat the air fryer to 375°F (190°C) for 3–5 minutes, then lightly spray the basket with oil.

Arrange a few breaded mini blooming onions in a single layer in the basket, spray generously with oil, and air fry for 10–14 minutes until golden and crispy, rotating if needed.

While the onions cook, stir together the mayonnaise, Greek yogurt, ketchup, horseradish, paprika, lemon juice, and a pinch of salt to make a creamy dipping sauce.

Serve the hot Air Fryer Crispy Mini Blooming Onions on a platter with the dipping sauce in a bowl in the center for easy sharing.