Preheat broiler. In a microwave-safe 1 1/2-quart casserole, combine cauliflower and the water. Cover and microwave on 100-percent power (high) for 12 to 15 minutes or until very tender, stirring once.
Meanwhile, lightly sprinkle turkey with salt and pepper. Place on an unheated rack of a broiler pan. Broil 4 inches from heat for 5 minutes. Turn turkey pieces over; broil for 4 minutes more.
Meanwhile, in a small bowl, stir together mayonnaise, 1/4 cup of the Parmesan cheese, and the bread crumbs. Spread over turkey. Broil for 2 to 3 minutes more or until topping is golden and turkey is no longer pink (170 degrees F).
Add butter and the remaining Parmesan cheese to cauliflower; mash until smooth. If desired, sprinkle with parsley and/or paprika. Serve cauliflower with turkey.