Can roast cauliflower for Maja Lukic's Mustard-Roasted Cauliflower today, reheat and dress tomorrow?

I would toss the cauliflower with at least some of dressing right after you roast it—it will take the dressing better while it's still warm! But, you can reserve some of the dressing for refreshing the dish tomorrow. I'd add the olives and toasted pistachios just before serving, so that the cauliflower doesn't get *too* briny and so that the nuts stay crunchy!