This is a classic—a legacy from early farming days, when oil was too rare to be used on salads. It is particularly good on soft leaf lettuces and on potato salads and slaws.
Whisk together in a small bowl:
      1/4 cup cider vinegar or white wine vinegar
      1/4 cup sugar
      2 tablespoons light cream
      2 teaspoons celery seeds or poppy seeds
      Salt and cracked black peppercorns to taste
Taste and adjust the seasonings. Use immediately or cover and refrigerate.