1. Remove the pork chops from the fridge 1 hour before cooking. Place on a plate and cover with a clean tea towel. Mix together the cheese, mustard, plain flour, oregano and seasoning. Set aside.
2. Meanwhile melt 25g of the butter and 1 tbsp of the olive oil in a saucepan and cook the onions over a medium heat for about 10-15 minutes, stirring occasionally, until golden and softened. Pour in the stock, Worcestershire sauce and seasoning. Bring to the boil, stirring and simmer for 2 minutes.
3. Remove the pan from the heat. Place the cornflour in a small bowl and stir in 4-5 tbsp of the gravy until smooth. Pour back into the pan stirring constantly until blended. Return to the heat and bring back to the boil, stirring constantly, until required thickness. Simmer for 1 minute.
4. Cook the parsnips and potatoes in a large saucepan of boiling water for 15-20 minutes, until tender.
5. Preheat the grill. Heat the remaining oil in a large frying pan and fry the pork chops for about 8-10 minutes, turning occasionally until golden on both sides.
6. Meanwhile drain the potatoes, add the creme fraiche, remaining butter and seasoning. Cover and bring the creme fraiche to the boil in the pan. Using an electric whisk or masher, mash the parsnip and potatoes, until smooth.
7. Divide the cheese filling between the pork chops spreading over the meat evenly. Place under the grill and cook for 3-5 minutes, until golden.
8. Serve with mash and onion gravy spooned over. Scatter over fresh oregano leaves to garnish.
