Part of my job duties at work are to have the sauces prepared for the make your own pasta bar. These include marinara, alfredo, and pesto. Today I will be talking about the alfredo sauce specifically.
Alfredo sauce is typically referred to a cream sauce that includes Parmesan cheese and butter. However, the reality is classically there is no such thing as an alfredo sauce. Usually the prepared dish was fettuccine alfredo which did not include a sauce. Instead the noodles were tossed with butter and cheese. As the cheese melted, it emulsified the liquids into a thick consistency. Sometimes cream would be added in addition to, or instead of the cheese.
Today alfredo sauce is a completely separate entity and often sold in jars or otherwise prepared. This is a shame given how easily alfredo sauce can be prepared at home. At work I will prepare a big batch of several (6-8) gallons to have ready for the week. I will then heat a smaller amount for the day's use. I start with equal parts milk and heavy cream. To save time you can also use half and half which is equal parts milk and cream. I will then heat the mixture slowly over low heat. I will prefer to use our large steam kettles. This help me avoid scorching the bottom of my sauce.
Once the dairy is at a simmer, at about 190 to 200 degrees, I start adding my spices and cheese. For spices I used salt, white pepper (very important it be white), and nutmeg (just a smidge). I will use good quality grated Parmesan cheese. For the 6-8 gallons, I usually used about 2 1/2 pounds. You can use shredded cheese, but just know it will take longer to incorporate. When adding your salt keep in mind that you want to add it sparingly at first since the cheese will also add saltiness to your sauce. You can adjust the seasonings later. Now, when you add the cheese, don't just dump it in all at once. Add it a little at a time and stir the sauce until it is incorporated in. Repeat this process until all of your cheese has been added.
After all of your cheese and spices have been added it is time to thicken the sauce. Now, traditionally it is only thickened with cheese and some reduction of the dairy and you can certainly choose to do that. At work I will usually used a cornstarch slurry to help it along. While the sauce is still hot, I will stir in the slurry until the sauce has reached the desired consistency. Now it is very important you add your slurry while the sauce is still hot. Otherwise the sauce will not thicken. Now if you ever find that you over estimated how much cornstarch you needed and over thicken your sauce, you can just thin it out with more dairy or even a bit of water. You can thicken your sauce using various other methods (roux, beurre manié), but the slurry is honestly the easiest.
When the sauce is at the desired consistency, you need to taste it. This is where you can adjust the seasoning. You can add salt and pepper if needed. The reason you want white pepper is so that your sauce remains white. Black pepper will show up as black flecks in your sauce giving it the appearance of cream gravy. As far as the nutmeg goes, you want to add enough to barley be perceptible. Nutmeg's flavor goes very well with dairy and you only need a small amount as to not overwhelm the flavor of the sauce.
If you want to make this sauce at home, here are some amounts to help you along the way:
1 cup milk
1 cup heavy cream
2 cups half and half
1/2 cup grated Parmesan cheese
Salt and pepper to taste
1 pinch nutmeg
2 tbsp cornstarch
Serve over your favorite pasta with your favorite ingredients!