You can reheat broccoli salad in several ways  The oven way: Reheat the salad in a casserole dish covered with tinfoil for 20 minutes at 400F, or until the broccoli is heated all the way through. The microwave way: Place the broccoli salad in a microwave-safe container. Cover with a lid and reheat at a high temperature for 2 minutes. Check if the broccoli is heated all the way through, then reheat them one more minute if necessary. Check again, and continue heating in intervals until the broccoli salad is hot.