01 - Preheat oven to 425°F. Line a large baking sheet with parchment paper and lightly coat with olive oil spray.
02 - Slice onions into 1/2-inch rings and separate the rings from each other.
03 - Arrange three shallow bowls: bowl 1 with flour, 1 teaspoon salt, and 1/2 teaspoon black pepper; bowl 2 with whisked eggs and milk; bowl 3 with panko breadcrumbs, smoked paprika, and 1/2 teaspoon garlic powder.
04 - Dredge each onion ring in flour mixture, dip into egg wash, then press firmly into panko mixture to coat evenly.
05 - Place coated rings in a single layer on the prepared baking sheet. Lightly spray tops with olive oil.
06 - Bake for 12-15 minutes until golden brown on bottom.
07 - Flip each ring, spray tops with olive oil, and bake for 8-10 minutes until crispy and golden on both sides.
08 - Whisk together mayonnaise, sour cream, buttermilk, chives, parsley, dill, garlic powder, onion powder, salt, pepper, and lemon juice until smooth and creamy. Refrigerate until ready to serve.
09 - Serve hot, crispy onion rings immediately with chilled ranch dressing for dipping.