Peel the onions and slice them into 1-inch thick rings. Carefully separate the rings and set them aside.

In a large bowl, combine the flour, paprika, garlic powder, onion powder, salt, black pepper, and cayenne pepper. Mix well.

In another bowl, whisk together the buttermilk and egg until smooth.

Place the breadcrumbs in a third bowl.

Dip each onion ring into the flour mixture, shaking off excess, then into the buttermilk mixture, and finally coat with breadcrumbs. Ensure each ring is well coated.

Heat about 2 inches of vegetable oil in a deep skillet or pot over medium heat until it reaches 350°F.

Fry the onion rings in batches for about 3-4 minutes or until golden brown and crispy. Remove and drain on paper towels.

For the dipping sauce, combine mayonnaise, ketchup, Dijon mustard, Worcestershire sauce, lemon juice, salt, and pepper in a small bowl. Mix until smooth.

Serve the crispy onion bites warm with the zesty dipping sauce.