Cold steak and cucumber salad with ponzu-mustard dressing

Trim the connective tissue (sinew) from the cold leftover steak.

Slice the steak very thin with a sharp knife and arrange on a plate.

Slice the cucumber very thin, seeds left in (a mandolin works), and lay it across the steak.

Slice the scallions very thin by pulling the knife backwards through them rather than chopping.

Put the sliced scallions in water with an ice cube so they curl and crisp.

Finely dice the shallot and put it in a bowl.

Make a quick ponzu of equal parts citrus juice, mirin and soy sauce with some hondashi in place of steeped kombu and katsuobushi.

Turn it into a dressing with roughly two parts each soy sauce, mirin and yuzu juice, one part whole-grain mustard and about four parts extra virgin olive oil; taste and add a pinch of salt.

Spoon the dressing over the steak; it does not need to be emulsified.

Top with the scallions, a touch of flaky sea salt and a few cracks of black pepper.