In a large bowl add broccoli, onion, bacon, cheese and raisins.
In a separate bowl, mix vinegar, sugar and mayo. Stir dressing until well blended.
Pour dressing over broccoli mixture and stir.
Refrigerate at least 4 hours. It is best if you can regrigerate overnight. This recipe does not yield a really runny salad like some similar recipes do. When you are ready to serve, toss it and garnish with a bit of shredded cheese.