Prep and Tenderise the Meat
Place the chicken thighs between two sheets of plastic wrap or baking parchment. Using the flat side of a meat mallet or a rolling pin, gently pound the meat until it reaches a uniform thickness of roughly 1/2-inch (1.25 cm). Season both sides evenly with the kosher salt and black pepper. Let it rest at room temperature for 15 minutes.
Pounding breaks down tight muscle fibers, ensuring the chicken cooks rapidly and evenly before the panko coating burns. Pre-salting draws moisture into the cells, keeping it incredibly juicy.
Flattened, even cutlets with no thick ridges remaining.