Toast 1 cup sliced almonds in a shallow pan over medium heat for 5-6 minutes, until fragrant. Remove from heat and reserve.
Combine 3/4 cup golden raisins 6 tbsp sherry vinegar in a small sauce pan, bring to a boil, remove from heat and allow to steep for 10-15 minutes
Combine 1/2 cup mayonnaise, 2 tbsp milk, 1 tbsp sugar, 1 tbsp white wine vinegar and season with Kosher salt and freshly ground black pepper in a large bowl. Stir to combine. Add 1 cup chopped celery and 2 cups red seedless grapes sliced in half and combine with dressing.
Drain raisins from vinegar and add to dressing.
Add roasted broccoli and red onion to dressing and toss all to combine.
Sprinkle with toasted almonds and gently toss to combine.