PREPARATION:

1. Preheat oven to 450°F. Place roast, bone-side-down, in shallow roasting pan. Combine mustard, tarragon and garlic in small bowl; spread over all surfaces of roast, except bottom. Insert meat thermometer into thickest part of roast, not touching bone or fat. Roast 10 minutes.
2. Reduce oven temperature to 350°F. Roast 2-1/2 to 3 hours for medium or until internal temperature reaches 145°F when tested with meat thermometer inserted into thickest part of roast, not touching bone.
3. Transfer roast to cutting board; cover with foil. Let stand 10 to 15 minutes before carving. Internal temperature will continue to rise 5° to 10°F during stand time.
4. To make gravy, pour drippings from roasting pan, reserving 1 tablespoon in medium saucepan. Add wine to roasting pan; place over 2 burners. Cook over medium heat 2 minutes or until slightly thickened, stirring to scrape up browned bits; set aside.
5. Add shallots to reserved drippings in saucepan; cook and stir over medium heat 4 minutes or until softened. Add flour; cook and stir 1 minute. Add broth and wine mixture; cook 5 minutes or until sauce thickens, stirring occasionally. Pour through strainer into gravy boat, pressing with back of spoon on shallots; discard solids.
6. Carve roast into 1/2-inch-thick slices. Serve with gravy and mashed potatoes, if desired.