01 - Preheat oven to 425°F. Line two baking sheets with parchment paper and lightly coat with olive oil spray.
02 - Separate onion slices into individual rings and set aside.
03 - Arrange three shallow bowls: combine flour, salt, and black pepper in the first; whisk eggs and buttermilk in the second; mix panko breadcrumbs with smoked paprika and garlic powder in the third.
04 - Dredge each onion ring in the flour mixture, dip into the egg-buttermilk mixture, then coat with seasoned panko, pressing gently to adhere.
05 - Arrange coated onion rings in a single layer on prepared baking sheets. Lightly spray with olive oil.
06 - Bake for 10 minutes, flip each ring, and continue baking for another 8-10 minutes until golden and crispy.
07 - While onion rings bake, whisk together all ranch dip ingredients in a bowl. Adjust seasoning to taste and refrigerate until ready to serve.
08 - Serve baked onion rings hot with chilled ranch dip on the side.