Cut tenderloin into medallions about 1.5 inches thick. Season with salt and pepper

Heat oil and 1T butter in a large skillet over high heat. When butter gets foamy add meat and sear until brown (2-3 minutes). Turn meat and sear another 2 minutes. Transfer pork to a plate

Melt remaining butter, add shallots and a pinch of salt. Stir for 30 seconds. Add mushrooms. Cook until mushroom liquid evaporates and mushrooms are golden. Sprinkle with flour and add Marsala. Boil until almost evaporated.

Add chicken broth and reduce to almost half. Stir in cream and parsley. Return pork to pan to cook. Flip once.