Have the butcher remove the bone and then tie it back on. This will give you more flavor, but allow you to easily remove the bone for carving.
Combine peppercorns and next 5 ingredients. Place roast, bone side down, on a rack in a shallow roasting pan. Spread peppercorn mixture over roast.
Bake at 325° for 2 1/2 to 3 hours or until a meat thermometer inserted into roast registers 140° or until desired degree of doneness.* Remove from pan and let stand for 15 to 20 minutes before slicing.**
Strain pan juices from roasting pan into a measuring cup. Skim off any fat drippings from top of juices, and reserve drippings for Yorkshire Pudding. Return pan juices to roasting pan; set pan over 2 burners. Add wine and broth to pan, scraping up any browned bits from bottom of pan, and boil 5 minutes or until mixture is reduced to 1 cup.
Stir together water and cornstarch; add to broth mixture, stirring constantly, 1 minute or until mixture boils and thickens. Remove from heat and serve with roast. Garnish, if desired.
*Note: Large cuts of meat will continue to cook from residual heat. Final temperature will rise 5° to 10°.
**Allowing meat to rest before carving brings juices back to the center, holding in flavor.