Directions

1. In a bowl, combine the olive oil, pepper, salt, garlic powder, and dried thyme.
2. Place the onion slices in the bottom of a baking dish.
3. Place the tenderloin on top of the onions and rub the meat with the oil/spice mixture.
4. Add the water to the bottom of the pan.
5. Bake in a 425-degree oven for 15 minutes, then reduce the heat to 350 degrees and continue baking for another 45 minutes (until a meat thermometer reaches an internal temperature of 135 degrees Fahrenheit for medium rare).
6. In a large skillet, melt the butter and then add the mushrooms. Cook for about 5 minutes and then add the dried thyme, the red wine, the onion soup mix, and the water. Cook for another 8 to 10 minutes, until the sauce is thickening.
7. Serve the sauce with the tenderloin.