Once the oil is hot and ready (flick in a drop of water—if it crackles, it’s ready), toss 6–8 pickle rounds in the seasoned cornstarch, then transfer to the buttermilk and egg mixture, turn to coat both sides, then finally coat in panko, gently pressing the rounds. Lay the breaded rounds into the hot oil and fry about 2 minutes per side—just until golden on each side (turning them only once will keep them crispy, not greasy). Drain the fried pickle chips on a wire rack or paper towels as you continue breading and frying the remaining rounds. Serve immediately.