Preheat your oven to 200°C (390°F) and line a baking sheet with parchment paper or a silicone mat for easy cleanup.
Slice the large yellow onions into 1/4-inch thick rings, keeping them intact but separated into individual rings for easier coating.
Set up your coating station: place the flour in a bowl, beat the eggs with a splash of water in another, and spread the panko breadcrumbs seasoned with salt, pepper, and smoked paprika in a third.
Dip each onion ring into the seasoned flour, shaking off any excess to ensure a light coating.
Next, coat the floured onion ring in the beaten egg mixture, letting any excess drip off.
Finally, dredge the onion ring in the panko breadcrumbs, pressing lightly to help the coating adhere well.
Place each coated onion ring on the prepared baking sheet, spacing them evenly apart.
Lightly spray the onion rings with neutral oil spray for a golden, crispy finish.
Bake in the preheated oven for 20–25 minutes, flipping the rings halfway through with tongs until they turn golden brown and smell toasty.
Once baked, remove from the oven and let the onion rings rest for 2 minutes, allowing the coating to set for a perfect crunch.
Serve these crispy baked onion rings hot, with your favorite dips or a squeeze of lemon to enhance their sweet, caramelized flavor.