Combine onion soup mix and water in a covered roasting pan; stir in mushroom soup. Place roast in pan on top of soup mixture. Cover and bake at 350 degrees for 4 hours, or until meat is very tender.
Remove roast from pan and shred; return to pan. Add noodles to pan; reduce heat to 300 degrees and bake for 20 to 30 minutes, checking and stirring every 15 minutes until noodles are tender. Add water if necessary to prevent drying out. Sprinkle with parsley before serving.