This incredibly simple dish requires only four ingredients and a few minutes of your time. * Cacio de Roma is a creamy, semi-soft cheese made from sheep's milk; it's a formaggio di pecora. This Italian gourmet cheese is made in the countryside of Rome and aged about one month. Often this cheese is referred to as a 'caciotta' because it is a small round cheese of approximately 4 pounds. Pecorino Romano cheese is the good substitute for Cacio de Roma.