01 - Separate the sliced onions into individual rings and set aside.
02 - In one bowl, whisk together flour, baking powder, salt, smoked paprika, and garlic powder. In a second bowl, whisk together buttermilk and eggs. Place panko breadcrumbs in a third bowl.
03 - Dredge each onion ring first in the flour mixture, then dip into the buttermilk-egg mixture, and finally coat with panko breadcrumbs. Press gently to ensure the crumbs adhere well.
04 - Heat about 2 inches of vegetable oil in a heavy-bottomed pot to 350°F.
05 - Fry the onion rings in batches for 2–3 minutes per side, or until golden brown and crispy. Do not overcrowd the pot.
06 - Remove rings with a slotted spoon and drain on paper towels. Sprinkle lightly with salt while hot.
07 - In a small bowl, whisk together mayonnaise, sour cream, buttermilk, chives, parsley, dill, garlic powder, onion powder, salt, pepper, and lemon juice until smooth. Chill until ready to serve.
08 - Serve the crispy onion rings warm with ranch dressing on the side.