Trim the tenderloins of silverskin and any excess fat. Cut the tenderloins into 2-inch-thick medallions. Flip each medallion onto a cut side and press down with the palm of your hand to flatten slightly. Season the meat with 3/4 teaspoon salt and 1/4 teaspoon black pepper.

Heat the olive oil and 1 tablespoon of the butter in a large saute pan over high heat. When the butter is melted and foaming, add half of the meat and sear until nicely browned, 2 to 3 minutes. Flip and cook the other side until the meat is well browned and slightly firm to the touch, about another 2 minutes. Transfer to a plate and repeat with the remaining pork.

Melt the remaining 2 tablespoons butter in the pan. Add the shallots and a pinch of salt and saute for about 30 seconds, using a wooden spoon to scrape up any browned bits from the bottom of the pan. Add the mushrooms and saute until all of the mushroom liquid has evaporated and the mushrooms are golden, about 3 minutes. Season with 1/2 teaspoon salt, sprinkle with the flour, and add the Marsala. Once the Marsala has almost completely evaporated, add the chicken broth and reduce by half, about 3 minutes. Stir in the cream and parsley, return the pork and any accumulated juices to the pan, and cook, flipping the pork once, until it's firm to the touch and still a little pink in the middle (cut into a piece to check), 2 to 4 minutes. Taste for salt and pepper and serve.

Serving Suggestion: Serve with buttered baby potatoes.