1/2 cup chopped onion
2 teaspoons salt
1/2 cup mayonnaise
1/4 cup vegetable oil
1/2 cup cider vinegar
2 tablespoons white sugar
2 tablespoons dried parsley
ground black pepper to taste
Bring a large pot of salted water to a boil. Add peeled and cut potatoes; cook until tender but still firm, about 15 minutes. Drain, and transfer to a large bowl. Add onions. In a large bowl, whisk together the mayonnaise, oil, vinegar, sugar, parsley, salt and pepper. Gently stir in the potatoes and onion. Let stand for 1 hour before serving to enhance flavors.