01 - Preheat the oven to 425°F. Line two baking sheets with parchment paper and set aside.
02 - Peel the onions and slice into 1/2-inch thick rings. Carefully separate each ring.
03 - In a shallow bowl, combine all-purpose flour, baking powder, smoked paprika, garlic powder, salt, and black pepper.
04 - In a separate bowl, whisk together the eggs and buttermilk until fully combined.
05 - Place panko breadcrumbs in a third shallow bowl.
06 - Dredge each onion ring first in the flour mixture, then dip in the egg mixture, and finally coat with panko breadcrumbs, pressing gently to ensure adherence.
07 - Lay the coated onion rings in a single layer on the prepared baking sheets. Lightly spray the tops with olive oil.
08 - Bake for 18 to 20 minutes, flipping the rings halfway through, until golden brown and crispy.
09 - While baking, whisk together mayonnaise, sour cream, buttermilk, chives, dill, parsley, garlic powder, onion powder, salt, black pepper, and lemon juice until smooth. Chill until serving.
10 - Serve the crispy baked onion rings hot alongside the chilled ranch dressing.