- Preheat oven to 450 degrees.
- Place rimmed baking sheet in oven to heat for 5 minutes. In a large bowl toss cauliflower with 2 tablespoons olive oil and ½ teaspoon salt.
- Carefully coat hot baking sheet with oil or cooking spray. Arrange cauliflower on sheet and roast 15 minutes. Toss and sprinkle with prosciutto pieces. Continue cooking for 10−15 minutes or until cauliflower is browned and crisp-tender.
- Meanwhile, in a small bowl, combine 1 tablespoon olive oil, vinegar, and mustard.
- Place arugula in a large mixing bowl. Toss with hot cauliflower and vinegar mixture. Season to taste with additional salt and freshly ground black pepper.
- Arrange salad on a platter. Top with Parmesan and pomegranate seeds.