Put the miso for the marinade in a dish large enough to hold the steaks in a single layer and mix in all the ingredients. Put the steaks in the marinade and turn them over several times. Cover, put in the fridge and leave for an hour or so.

To make the mayonnaise, mix together the egg yolk and mustard in a bowl. Continuously beating with a hand whisk or an electric beater, start adding the oil very slowly, a drop at a time. Wait until each drop is amalgamated and the mixture has thickened before adding the next. As it develops more body, you can add the oil in slightly larger quantities. Add the garlic, miso and rice vinegar, then add the lime to taste. Finally, mix in the chilli. Cover and set aside. This will make more than you need, but it will keep in the fridge for three days.

Heat a non-stick frying pan until it’s really hot. Lift the steaks out of the marinade, shaking off the excess. Cook quickly on each side for 30 seconds, then turn the heat down a little and cook for a further 2 mins (for rare steaks), turning them and basting over some of the leftover marinade. Set aside to rest. Clean the pan.

Warm the ciabatta in the oven, then slice horizontally. Spread the bread with a big dollop of the mayonnaise. Pile the spinach onto half of the slices.

Heat the frying pan again and brush the spring onions with oil. Fry them over a medium heat, turning all the time, until the base is tender, around 10 mins. They will really collapse but that’s okay – just don’t burn them.

Cut the steaks into thick slices (you can leave them whole if you like, but I prefer them sliced), put them on top of the leaves, top with the spring onions and sesame seeds and top with the other half of the bread. Serve immediately.