Combine the first 5 ingredients in a large bowl, tossing mixture to coat. Place the potato mixture in a shallow roasting pan. Bake at 400° for 30 minutes or until tender, stirring mixture occasionally. Cool to room temperature.
Combine the parsley, yogurt, green onions, salt, and black pepper in a large bowl. Add the cooled potato mixture, and toss gently. Serve salad at room temperature or chilled. Garnish with green onion, if desired.