Use freshly grated Parmesan cheese for better flavor and smoother sauce. Whisk constantly when adding cream and milk to prevent lumps. Avoid overheating after adding cheese to prevent separation. Thin sauce with milk or pasta water if too thick. Keep warm on low heat if not serving immediately, and stir occasionally. For more garlic flavor, roast garlic or add garlic powder. Alfredo sauce does not freeze well; consume leftovers within 3 days stored in the refrigerator.