HEAT oven to 350ºF.
SEASON meat with 1/2 tsp. pepper. Place on rack in shallow pan. Bake 2 to 2-1/2 hours or until 145ºF. Remove from oven. Cover with foil; let stand 10 min.
MEANWHILE, bring water, 1-1/2 cups apple juice, raisins and butter to boil in large saucepan. Stir in stuffing mixes, apples and nuts; cover. Remove from heat. Let stand 5 min. Fluff with fork; spoon into center of meat. Spoon any remaining stuffing into serving bowl. Cover meat and remaining stuffing to keep warm until ready to serve.
REMOVE 2 Tbsp. pan drippings; place in medium saucepan. Whisk in flour and mustard; cook on medium heat 1 min., stirring constantly. Stir in remaining apple juice and pepper; cook and stir 3 min. or until mixture comes to boil and thickens. Stir in parsley.
CUT meat into 1-rib portions. Serve with stuffing and apple gravy.