Mom's Potato Salad

1/4 cup cider vinegar 1/4 cup water 1/4 cup sugar1 teaspoon yellow mustard2 eggs, beaten1 cup creamy white salad dressing or mayonnaise3 pounds red potatoes, boiled, cooled, peeled and sliced 1/4-inch thick 1/4 cup onion, chopped, optional 1/4 cup celery, chopped, optionalSalt and pepper to tastePaprika1 boiled egg, sliced, optionalBring vinegar, water and sugar to a boil in a small saucepan. Slowly whisk in the beaten eggs, stirring constantly, and cook until mixture is thickened. Cool and add salad dressing.Toss dressing and potatoes in a large bowl, add onion and celery if desired. Season with salt and pepper. Garnish with paprika and a sliced boiled egg. Refrigerate until ready to serve.Serves eight to 10.Nutrition values per serving: 299 calories, 19 g fat (3 g saturated), 29 g carbohydrates, 2 g fiber, 4 g protein, 54 mg cholesterol, 271 mg sodium.