Place roast on an 18- x 11-inch piece of heavy-duty aluminum foil.
Stir together mustard and next 4 ingredients; spread over roast. Fold foil over roast to seal. Place in a shallow roasting pan, and chill at least 8 hours.
Remove roast from foil; place in roasting pan.
Bake, covered, at 450° for 20 minutes. Arrange uncooked Roasted Potatoes around roast, and bake, uncovered, 25 more minutes or until potatoes are tender and roast is done. Remove from oven; cover and let stand 15 minutes before slicing. Garnish, if desired.