Pork with apple frizzled sage

Name: Pork with apple & frizzled sage
Ingredients: 3 small parsnips, trimmed; 3 tbsp olive oil; 250g pork fillet (thick end); 85g gruyère cheese, preferably reserve; 1 tbsp chopped fresh sage, plus six leaves; 2 knobs of butter; 2 small Cox's apples, cored and sliced; ½ a small Savoy cabbage, cored and finely shredded; small wine glass of dry white wine or cider