Pork in a Creamy Mustard Sauce

To cook pork in a creamy mustard sauce, season the pork with salt and pepper, then cut into medallions. Heat a good knob of butter in a frying pan and sear the pork medallions until golden brown. Remove the pork from the pan and set aside. Add the chopped shallots and another knob of butter if required, then cook gently until softened. Add a splash of white wine vinegar, followed by two tablespoons of Dijon mustard and the jar of Béarnaise sauce. Stir well and simmer until the sauce thickens, adding a little more white wine vinegar or water if needed. Return the pork to the pan and gently simmer in the sauce for approximately 5 minutes, or until cooked through. Meanwhile, boil the potatoes in a separate pan. Serve the pork and creamy mustard sauce with the potatoes and a sprinkle of freshly chopped parsley.