Slice the pork tenderloin into 1cm thick rounds. Heat a splash of olive oil in a pan over a medium heat and fry the pork for 2 minutes on each side. Add the zest and juice the lemon, fresh oregano leaves and dry cider, then cook over a high heat for 3 minutes.
Meanwhile, grate the golden delicious apples and beetroot. Stir through the yogurt with a squeeze of lemon juice and some sliced spring onion. Season and serve with the pork.