Roast Tenderloin of Beef
Melt 2 tablespoons butter in same skillet. Add mushrooms and sauté until tender, about 15 minutes. Return onions to skillet. Add flour and stir 3 minutes. Stir mushroom mixture into wine mixture. Simmer over medium heat until thickened and reduced to 6 cups, stirring occasionally, about 1 hour. Season to taste with salt and pepper. Can be prepared 1 day ahead. Cover and refrigerate.
Preheat oven to 400F. Rub tenderloin with olive oil. Season with salt and pepper. Place in roasting pan. Roast until thermometer inserted into thickest part of meat registers 125F., about 40 minutes for rare.
Remove from oven and let stand 10 minutes.
Rewarm sauce over low heat; mix in any juices from roasting pan. Slice tenderloins crosswise into ˝ inch thick slices.
Overlap beef slices on platter. Spoon some sauce over. Serve,
passing remaining sauce separately. 10 servings.