Place the yogurt, horseradish sauce and 1 tbls of rapeseed oil in a bowl and whisk to combine. Crush the hazelnuts into chunks and set aside.
Core the Pink Lady apple and slice thinly. Heat 1 tsp of rapeseed oil in a medium sauce pan until very hot and then add the Tenderstem. Immediately cover with a lid and shake it well to turn over the florets.
Cook on full heat for 30 seconds and then shake again. Cook for a further 30 seconds and remove from the heat. The Tenderstem should have crisp, golden brown bits and be vibrant green. The texture should be al dente. If it is still not gone golden return to the heat in 15 seconds bursts until it is ready.
Sprinkle with a pinch of sea salt and toss one more time.
Place a pile of watercress on each plate, lay the Tenderstem over the top and sprinkle the apple and hazelnuts over the top. Dress generously with the horseradish, yogurt sauce and serve whilst still hot.