This type of “Musubi sandwich” started in South Korea but is now taking all of Asia by storm!
Coat each slice of spam with flour, dip in the beaten egg and then into the panko for a standard breading procedure.
Place the oil in a medium sized sauté pan, turn the heat to medium, allow the oil to heat to 300° F (about 4 minutes) then shallow pan fry the spam until golden brown and place them on paper towels or a wire rack to remove excess oil.
Combine the ketchup and Worcestershire sauce to make a quick katsu sauce.
Place the nori sheets rough side facing up, make a cut from the middle of the top side of the nori sheet to the center of the nori sheet. Visually divide the nori sheet into 4 quarters, place the spam katsu in the top left quarter, the rice in the bottom left corner topped with the katsu sauce, the lettuce and tomato in the bottom right corner and the American cheese in the top right corner. Fold the top left corner down to place it on the bottom left, then fold the bottom left to the bottom right, then the bottom right gets folded upwards on to the top right and serve as is!