Cook rotini according to package directions; drain and return to pan. Stir in Alfredo sauce, milk, mozzarella, ham, Italian seasoning, and pepper.
Transfer rotini mixture to four 7 to 8 ounce au gratin dishes or ramekins or a 1 1/2-quart au gratin dish. Sprinkle with Parmesan cheese. Cover and chill for up to 24 hours.
To serve, preheat oven to 350°. Cover with foil and bake for 25 to 30 minutes for the individual dishes or about 45 minutes for the casserole dish or until mixture is heated through. Let stand for 10 minutes. Stir before serving.