For the Chicken:

1. Prepare the chicken:
   Place the chicken breasts between two pieces of plastic wrap or parchment paper. Pound them to an even thickness using a meat mallet or rolling pin. This ensures even cooking and keeps the chicken tender.

2. Set up a breading station:
   In one shallow dish, add the flour and season it with salt and pepper. In a second dish, place the beaten eggs. In a third dish, add the panko breadcrumbs.

3. Bread the chicken:
   Dredge each chicken breast first in the flour, shaking off any excess, then dip it into the beaten eggs, and finally coat it in the panko breadcrumbs. Press the breadcrumbs gently to ensure they stick.

4. Fry the chicken:
   Heat about ½ inch of vegetable oil in a large frying pan over medium heat. Once the oil reaches around 350°F, carefully add the breaded chicken breasts. Fry each side for 3-4 minutes, or until golden brown and fully cooked, with an internal temperature of 165°F.

For the Katsu Sauce:

1. Prepare the sauce:
   In a small bowl, whisk together the ketchup, soy sauce, Worcestershire sauce, mirin, Dijon mustard, and sugar. Adjust the seasoning to taste.

2. Serve:
   Once the chicken is fried, slice it into strips and drizzle the katsu sauce over the top. Serve with steamed rice and shredded cabbage on the side.