Coat inside of 4-quart electric slow cooker with cooking spray. Add stuffing mix, onion, celery and cranberries. Combine broth and melted butter. Pour over stuffing and stir gently. Remove string from defrosted turkey breast. Rinse and place in slow cooker on top of dressing. Cover and cook on high for 1 hour; reduce to low and cook 5 to 6 more hours. Meat thermometer should register 170 degrees internally. Remove turkey to serving platter. Stir stuffing gently and let stand 4 or 5 minutes. Prepare gravy. Yield: 5 to 6 servings.