1 c. cider vinegar
1 c. sugar
1/3 c. mayonnaise
2/3 c. sour cream
1 1/2 tsp. celery seed
1/2 tsp. salt
4 or 5 Imperial sweet onions, sliced 1/4 inch thick

Place sliced onions in bowl; set aside. Bring vinegar and sugar to boil. Pour mixture over onions; mix well. Refrigerate 8 hours. Drain excess moisture; combine with dressing. Chill until serving time.