A colorful dish that’s easy to prepare and always welcome at a potluck or hot-weather picnic. It’s a good make-ahead recipe, too, that keeps for several days in the refrigerator.
Bring a large pot of water to a boil. Add the cauliflower and broccoli and blanch for 1 minute. Drain, then immediately plunge into cold water to stop the cooking. Drain well.
In a large salad bowl, combine all the vegetables with the olives. In a small bowl or jar, mix together the vinegar, oil, sugar, salt, pepper, herbs, and water. Mix well. Pour over the vegetables. Cover the bowl and refrigerate for 8 to 24 hours before serving.