Butterfly chicken breasts, cover with plastic, and flatten with a meat tenderizer (mallet). If they are too big, cut into 1/2 each. Sprinkle salt and pepper on both sides of the meat.
Coat the meat with flour, dip in egg, then cover with bread crumbs.
Heat deep frying oil to 350 F (180 C), and deep fry crumb-covered meat.
Fry until the color turns golden brown and the meat floats in the oil, about 5-8 minutes, turning once or twice.
Set the meat on a cooling rack for a minute. Cut into 5-6 pieces. Drizzle Tonkatsu sauce if you like.