1. For the dressing, put the vinegar, sugar, raisins, cinnamon stick and thyme into a small pan, bring to the boil then immediately take off the heat.
2. Whisk in the mustard and then drizzle in the sunflower and olive oils. Season and set aside.
3. Heat the oil in a pan until gently smoking, season the steak and add it in carefully. Cook for three minutes on each side for medium rare, but this will depend on how thick it is, and also on how you like your steak, so you will have to use your judgement.
4. When it is cooked to your preference, remove the steak from the pan and allow it to rest, covered, in a warm place.
5. Peel and thinly slice the celeriac into a bowl (a mandolin is perfect for this).
6. Trim and shred the cabbage, then wash and dry and add to the celeriac.
7. Slice the pears and the radishes, then add to the bowl along with the walnuts.
8. Thinly slice the steak and add it to the vegetables along with any juices. Spoon over some of the dressing, season, mix and it’s ready to eat. I like to serve this with a little horseradish creme fraiche. Just mix a tablespoon of horseradish sauce into a 200ml tub of creme fraiche and there you have it.