Preheat oven to 250 degrees F. Season tenderloin generously with salt and pepper and fold the tail piece under itself to create a roast of uniform thickness. Tie beef with twine all the way around, and tuck sprigs of thyme under the twine all over roast. Place beef on a roasting pan and roast until the thickest part measures 130 degrees on an instant-read thermometer (for medium-rare), about 1 3/4 - 2 hours.

Transfer to a carving board, tent loosely with foil and let rest for 30 minutes. Slice and serve, drizzled with the Red Wine Jus.

Makes 6-8 servings.

Red Wine Jus

*2 tablespoons unsalted butter

* 4 medium shallots, thinly sliced

* 2 cups full-bodied red wine

* 2 tablespoons red wine vinegar

* 1 teaspoon fresh thyme leaves

* 4 cups beef and veal stock or 2 cups reduced-sodium beef broth and 2 cups reduced-sodium chicken broth

Melt butter in a large saute pan over medium heat. Add shallots and cook, stirring occasionally, until translucent, about 5 minutes. Turn heat to high and add wine and vinegar and boil vigorously until reduced to 1/4 cup, about 10 minutes. Add thyme and stock or broth and cook until reduced to 1 cup, about 20 minutes. Strain and keep warm until ready to serve. (Jus can be made ahead and covered and refrigerated. Just heat before serving.)