Split chicken breast into 4 equal portions (4oz each). With a meat mallet, lightly flatten chicken breast and set aside.
In three small bowls; scramble raw egg in one, flour in the second and panko crumbs in the third. Season bowl that contains flour with salt and pepper.
Drench chicken in flour, then egg, and then finally coat with panko.
Heat oil in a medium sauté pan on medium (350 degrees).
Fry the coated chicken patty to a golden brown and to a internal temperature of 170 degrees.
Sauté onion rings in a small sauté pan on medium heat with olive oil.
Butter and toast the KING'S HAWAIIAN Sweet Pretzel Hamburger Buns.
Spoon mustard onto the bottom of the KING'S HAWAIIAN Sweet Pretzel Hamburger Buns, and top with arugula.
Place chicken schnitzel on arugula.
Place pickles on top of schnitzel and then onions.
Spoon mayonnaise onto the top bun.
Finish with top bun. Enjoy!