Complex sentence: Less expensive cheeses, such as U.S.-made Parmesan cheese, an imitation of Parmigiano-Reggiano, are often used; the cheese is sometimes mixed with flour as a thickener.
Split into simpler sentences: Less expensive cheeses such as American-made Parmesan cheese, an imitation of Parmigiano-Reggiano, are often used. Additionally, the cheese is sometimes mixed with flour as a thickener.