Place the cauliflower in a steamer basket set in a saucepan over 1 inch of boiling water. Steam 5 minutes, until tender but still firm. Drain, cool slightly, and place into a large bowl.
Mix the mayonnaise with the Italian salad dressing and Parmesan cheese in a bowl. Add the carrots to the bowl with the cauliflower, and toss with the mayonnaise mixture until evenly coated. Cover, and refrigerate at least 2 hours or overnight to allow flavors to blend.
