Simmer potatoes in salted water to cover until tender, 20 to 25 minutes depending on size of potatoes. Drain, rinse with cold water to stop the cooking and cool the potatoes. Peel, if desired, and cut into 3/4-inch chunks. In a large bowl, combine sour cream, mayonnaise, mustard, salt and pepper, mix well. Add potatoes, cheese, chives and 1/4 cup parsley, toss well. Stir in eggs, if desired. Cover and chill at least 2 hours or up to 8 hours before serving. To serve, sprinkle with bacon and reserved 2 tablespoons parsley, Yield: 16 servings, about 8 cups salad.