1. Heat oven to 450 degrees F.Beef:
2. Rub tenderloin with oil. Season with salt and pepper. Cover surface of tenderloin with garlic, pressing to adhere. Place meat on rack in roasting pan.
3. Roast in 450 degree F oven for 40 minutes or until internal temperature registers 140 degrees F on instant-read thermometer for medium-rare. Let meat stand in warm place 10 minutes before slicing for serving (internal temperature will rise to 145 degrees F).Sauce:
4. While meat is roasting, in medium-size saucepan, heat butter over medium heat. Add shallot and garlic; cook over medium-low heat 5 minutes, until softened. Add thyme, peppercorns, port and all but 4 tablespoons broth. Bring to a boil. Lower heat; simmer 15 minutes.
5. In bowl, stir together reserved 4 tablespoons beef broth and flour.
6. Strain broth mixture with shallots through sieve placed over a bowl; discard solids. Pour back into saucepan. Stir in broth-flour mixture. Bring to a simmer; cook, whisking occasionally, 2 minutes or until slightly thickened.
7. Serve sliced meat with port sauce on the side, and roasted potatoes, if desired. Makes 16 servings.