Cook the potatoes in a large saucepan of salted, boiling water until tender; usually 15-20 minutes. Drain and allow to cool a little. Mash together with the crème fraiche, butter and seasoning until smooth. Cover and reserve to one side.
Pre-heat the oven to 200° C.
Make a horizontal incision in each pork loin chop so that you can stuff them with the Gruyere. Heat a heatproof frying pan over a moderate heat until hot then melt the butter with the olive oil. Sear the chops for a few minutes on both sides, then transfer to the oven to finish cooking for 10 minutes.
Meanwhile, combine the crème fraiche and Dijon mustard in a small saucepan. Heat gently over a low heat, whisking until you have a smooth sauce. Season to taste and keep warm to one side.
Remove the pork chops when ready and re-heat the mash if necessary. Arrange the pork chops on serving plates and garnish with a pinch of paprika. Spoon the mash to one side, then serve the sauce on top of the pork and to the side as well. Garnish the mash with the parsley before serving.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home.