Place the 2 chicken breasts on a cutting board. Cut them in half, width-wise so that you have four thin chicken cutlets.
Place a piece of plastic wrap over all of the chicken pieces on the cutting board. Use a meat mallet to pound the chicken until they are about ¼ - ½” thick.
Remove the plastic wrap. Then sprinkle both sides of the chicken with salt and freshly-cracked black pepper.
Get out 3 separate shallow bowls (I sometimes use cake pans or pie tins) and pour 1 cup flour in one, the 2 beaten eggs in another, and the 1 cup panko breadcrumbs in the final pan.
Pick up one of the chicken pieces and first dip it in the all purpose flour, making sure it is evenly coated on both sides.
Next, rub the chicken in the beaten egg, making sure it is evenly coated on both sides.
Finally, dip the floured and egged chicken in the panko breadcrumbs. Press the chicken into the breadcrumbs so that the breadcrumbs stick and the chicken is evenly coated. Make sure there is no surface area without breadcrumbs.
Repeat this process with as many chicken pieces as can fit in your pan at once.
Put a cast iron skillet on the stove and pour about 1 ½ inches of oil into it. Heat the oil until it reaches an internal temperature of 350 degrees Fahrenheit.
Add the chicken into the oil and cook for 2-3 minutes until the katsu is browned on one side. Then flip the katsu over and cook again on the other side until browned. Your chicken is done when it reaches an internal temperature of 350 degrees Fahrenheit.
Repeat with the remaining chicken pieces.