Spread the pickle slices on paper towels and press dry. Let them sit for 5 minutes, then pat again until the surface feels tacky, not wet.

Whisk the flour, cornstarch, garlic powder, onion powder, smoked paprika, cayenne, salt, and black pepper together in a wide shallow bowl. In a separate bowl, whisk the buttermilk and egg until smooth.

Pour vegetable oil into a deep skillet to a depth of 2 inches and heat over medium-high until it reaches 375°F (190°C).

Working in batches, dip each pickle slice into the buttermilk mixture, let the excess drip off, then press it into the seasoned flour on both sides and shake off any loose coating. Set on a wire rack while you coat the rest of the batch.

Lower 8 to 10 coated pickle slices into the hot oil. Fry for 2 to 3 minutes total, flipping once at the 1-minute mark, until deep golden all over. Transfer to a paper-towel-lined plate and let the oil return to 375°F before the next batch.

Move the fried pickles to a serving plate, remove the paper towel so the bottoms stay crisp, add a pinch of smoked paprika over the top, and serve immediately with the ranch dressing on the side.