Pat the pickle slices dry with a paper towel to remove excess moisture.
In a shallow dish, combine the flour, garlic powder, paprika, and cayenne pepper (if using).
In another shallow dish, whisk together the buttermilk and egg.
Place the panko breadcrumbs in a third shallow dish.
Dip each pickle slice into the flour mixture, then into the buttermilk mixture, and finally coat with panko breadcrumbs. Press gently to ensure an even coating.
Heat about 1 inch of vegetable oil in a deep skillet or pot over medium heat until it reaches 350°F.
Fry the coated pickles in small batches for 2-3 minutes per side or until golden brown and crispy. Avoid overcrowding the pan.
Remove the fried pickles with a slotted spoon and place them on a paper towel-lined plate to drain excess oil.
Serve hot with your favorite dipping sauce, such as ranch or spicy aioli.