These patties are really easy to throw together for a quick weeknight ... Serve the katsu with a scoop of white rice, cabbage, the pickled cucumbers (I like to toss a bit of the pickling liquid ...
For the relish, quarter the cucumber lengthways, then thinly slice and place in a bowl along with the onion. Season with a few generous pinches of salt. Mix well and leave to rest for 15 minutes.