Beef Tenderloin Roast with Marsala Cream Sauce and Smashed Potatoes

1. Allow the beef to come to room temperature for at least 1 hour. Preheat the oven to 475° F
2. Arrange the potatoes on a large sheet pan or roasting pan. Place the beef in the center. If you have a roasting rack, put the beef on it. 
3. In a bowl, mix the butter, dijon, Worcestershire sauce, thyme, and garlic. Pour the butter evenly over the beef. Season with salt and pepper. Insert a meat thermometer. Roast until the beef registers 120° F to 125° F for medium-rare/rare, about 25-40 minutes, depending on the size of your roast. I like to cook my roast to 115° F. Keep in mind it will continue to cook as it sits.
4. To make the cream sauce. In a skillet set over medium heat, combine the butter and mushrooms. Cook for 5 minutes, until golden. Add the garlic, thyme, salt, and pepper. Cook for 2 minutes. Add 1/4 cup marsala wine. Cook another 2 minutes until the mushrooms have caramelized. Add the remaining wine. Pour in the cream. Reduce the heat to medium-low and simmer until the sauce thickens. Season with salt and pepper. Keep warm. 
5. Finish the beef. Remove the beef from the pan. Place onto a serving plate and cover with foil. Let rest for 10 minutes.
6. Finish the potatoes. Toss the potatoes in the butter on pan. Using the back of a fork or a potato masher, smash each potato. Sprinkle with parmesan. Roast until the potatoes are crispy, 10 minutes. Season with sea salt.
7. Slice the beef and serve with the warm cream sauce and potatoes.