Slice the chicken breasts into thirds lengthwise. Cover with plastic wrap and pound them to a uniform thickness of ½ inch. The cleanest way to do this is to place the chicken in a ziplock bag with the air squeezed out. I was able to get three slices into a quart sized bag. When I was done I just stored them in the bag in the fridge until ready to use.
Make the egg wash for the chicken by combining the beaten egg, cornstarch, water, salt, pepper, and granulated garlic in a long pan. I used a glass loaf pan. Cover and refrigerate until ready to use. Stir just before using to incorporate the cornstarch which may have settled to the bottom. Place all the chicken slices into the egg wash at once, or one at a time if you prefer. It was easiest just to soak them all at once.
Pour the panko bread crumbs into a shallow pan. One at a time, pull the chicken pieces out of the egg wash and pat into the bread crumbs, coating both sides.
Fry the chicken pieces in a large skillet, preheated with oil to medium high. Use just about a half in of oil up the side of the pan. Cook the chicken until it is lightly golden brown then flip over and cook the other side. Don't crowd them in the pan or they won't get crunchy. Don't walk away. These cook fast and burn easily.
<span class="mceItemHidden" data-mce-bogus="1">Remove the cooked pieces of chicken to a heated plate in a 200 degree oven until all the pieces are cooked. Serve immediately with a little Katsu sauce over the top and extra for dipping.</span>