Boil potatoes in salted water for 15 minutes, or until tender. Rinse and drain under cold running water. Place in a large bowl. Add apples, celery or fennel, onion, and parsley. Toss.
To make the dressing, whisk together the olive oil, white wine vinegar, cream, lemon juice, salt and pepper in a small bowl. Pour over salad and toss.
Refrigerate for at least 2 hours before serving. Enjoy!