How to make it
Combine the margarine, mayo, and mustard together in a small bowl. Set it aside for later. In a separate bowl, combine the Lee Kum Kee Hoisin Sauce, tonkatsu sauce, and ketchup. Set it aside for later.
Place the pork slices onto a cutting board and pound them with a meat mallet until they have tenderized and are about ½ an inch thick. Shape and trim the pork so that it fits the shape and size of the bread. Season both sides with salt and pepper.
Pour the vegetable oil into a pan with sides so that it is about ½ an inch deep. Heat over medium heat.
Pour the flour, egg, and panko each into their own separate shallow dishes. Dredge each slice in flour, dusting off any excess. Then dip them into the egg, making sure that the flour has been absorbed.
Add the pork to the hot oil and cook for about 4-5 minutes on each side. When the pork is fully cooked, remove them from the pan and drain them on paper towels.
To assemble the sandwich, spread some of the mayo mixture onto one slice of bread. Add half of the shredded cabbage on top. Drizzle some of the tonkatsu sauce mixture on top of the cabbage then lay the pork on top. Drizzle more of the tonkatsu sauce on top of the pork. Top it with another slice of bread then cut it in half. Repeat this process to assemble the remaining sandwich. Enjoy!