We start by preparing the tonkatsu sauce and, to do this, we peel and chop the clove of garlic and crush it in a mortar together with the mustard seeds and ginger until we obtain a paste. We can use mustard powder or fresh ginger if we prefer and have it on hand.
Add the soy sauce, ketchup, Worcestershire sauce and honey. We stir to combine all the ingredients well and we already have the sauce ready. It’s pretty thick, so we can lighten with a little water, but this is totally optional.
Remove the bone from the chops and season to taste. We coat them in flour, beaten egg and panko, ensuring that they remain well empanadas on all sides.
Heat plenty of oil in a frying pan and fry the chops over medium-high heat until they are golden, turning so that they take color on both sides. Drain them on absorbent paper.
We assemble the katsu sando spreading a thin layer of sauce on the slices of bread (we can toast them previously or not), placing the breaded and fried chop on top and crowning with julienned Chinese cabbage. We close in sandwich with the other slice of bread. Cut in half and serve immediately.