Notes from the Test Kitchen:
These are some really good onion rings! In my opinion, they are better than I have had in most restaurants recently. I love that these are baked, not fried. I'm always looking for ways to eat a little healthier!
yellow onion - ends trimmed off, peeled, and cut crosswise into 1/2-inch slices
Whisk eggs with milk in a bowl until thoroughly combined. Place panko crumbs into a separate bowl.
Place onion rings into a large resealable plastic bag. Add flour, salt, and black pepper; seal bag and shake until rings are well coated with flour.
Drop flour-coated onion rings into egg/milk mixture, a few at a time, and toss lightly with tongs until coated. Place rings into panko crumbs and gently shake the bowl to toss the crumbs with the onion rings until rings are coated with crumbs.
Transfer coated onion rings to a large baking sheet; spray rings lightly with cooking spray.
Bake in the preheated oven until onion rings are tender and crumbs are lightly golden brown, 12 to 15 minutes.