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.