Alfredo Sauce

This happens when cheese is added to too-hot liquid or when the sauce is reheated over direct heat. Always remove the pan from heat before whisking in cheese, and reheat in a double boiler or in a low oven (200°F), whisking gently, for 5 minutes.

You can make it up to 2 hours before serving and keep it warm in a double boiler over barely simmering water, whisking occasionally. Do not refrigerate and reheat Alfredo; it breaks easily. If you must, make the butter-cream base ahead and store it in the fridge, then reheat gently and whisk in the cheese fresh.

You must use authentic Parmigiano-Reggiano (check the label for the official stamp); it's the only cheese with the right melting point and flavor. Domestic Parmesan or pre-grated cheese will not work—it's full of anti-caking agents that cause graininess.

Yes, but use 1 cup half-and-half and skip the milk, or use 1/2 cup heavy cream and 1 cup whole milk. The fat content affects richness and how much cheese you can incorporate, so adjust the cheese down to 3 ounces if the sauce seems thin.

Cool it completely and refrigerate in an airtight container for up to 2 days. Do not freeze. Reheat in a double boiler over barely simmering water, whisking constantly and adding a splash of milk if it thickens too much. Freshly made sauce always tastes better.

Classic Roman Alfredo is butter, cream, and cheese only—nothing else. Garlic or chicken makes it a different dish. Make the pure sauce first, then toss it with pasta and add grilled chicken or sautéed garlic on the side if you like.