Preheat convection oven to 400°F (200°C) and prepare a parchment-lined baking sheet.

Remove the stem end of the onion and peel the outer skin, maintaining the root base integrity.

Position onion cut-side down. Execute four primary vertical cuts toward the root, stopping 0.5 inches from the base. Subdivide into 16 symmetrical segments.

Invert the onion and manually expand segments to achieve a floral geometry.

Combine flour, paprika, garlic powder, cayenne, salt, and pepper in a medium bowl.

Whisk eggs in a separate vessel until homogenous. Place panko in a third vessel.

Sift the flour mixture over the onion, ensuring total coverage between segments.

Apply egg wash to all surfaces of the floured onion.

Uniformly coat with panko breadcrumbs, pressing lightly to adhere.

Transfer to the baking sheet and apply a high-coverage coating of olive oil spray.

Bake covered with foil for 15 minutes.

Remove foil and bake for an additional 15-20 minutes until internal core is tender and exterior reaches a golden-brown finish.