1 whole beef loin tenderloin roast (4 to 6 pounds)
Mushroom Sauce:
1/3 cup butter
¾ cup sliced mushrooms
¾ cup finely chopped onion
1 ½ tablespoons flour
¾ teaspoon salt
¼ teaspoon pepper
¼ teaspoon thyme
1 ½ cups beef broth
¾ cup red wine, such as burgundy
1 ½ teaspoons wine vinegar
1 ½ tablespoons tomato paste
1 ½ teaspoons chopped parsley
1. Place tenderloin on rack in roasting pan. Insert roast meat thermometer in center of meat so that tip is slightly more than halfway through meat.
2. Roast , uncovered, at 425°F 45 to 60 minutes. The roast will be rare when meat thermometer registers 140°F.
3. For Mushroom Sauce, heat butter in a skillet. Add mushrooms and cook over medium heat until lightly browned and tender, stirring occasionally. Remove mushrooms with a slotted spoon, allowing butter to drain back into skillet; set aside.
4. Add onion and cook 3 minutes; blend in flour, salt, pepper , and thyme. Heat until mixture bubbles. Remove from heat.
5. Gradually add, stirring constantly, beef broth, wine, and wine vinegar. Cook rapidly until sauce thickens. Blend in the mushrooms, tomato paste, and parsley. Cook about 3 minutes.
6. Serve slices of beef tenderloin with sauce spooned over individual servings.
16 TO 24 SERVINGS