As I mentioned today over in Huffington Post's new food pages, I once used to purchase the Knorr powdered mix for Alfredo sauce. This is almost like buying dehydrated water. Fettuccine Alfredo is the world's easiest cream sauce, and it's also one of the best.
In my opinion, the quality of the dish is dependent on the cheese, good Parmigiano-Reggiano. If you don't have that, make something else. The traditional Italian Alfredo doesn't use cream but I think the cream is essential for distributing the cheese. I also feel that dried pasta is too heavy for this—this dish calls for fresh pasta. Best to make it yourself, but good fresh pasta is available at most grocery stores now. This dish comes together fast—the hardest part about it waiting for the water to boil.
1 cup cream
salt to taste
freshly ground pepper to taste
2 ounces butter, cut into a few pieces
4-6 swipes of nutmeg on a Microplane or grater
12 ounces fresh pasta
2 ounces freshly grated Parmigiano-Reggiano
Put a pot of water on to boil. In a pan big enough to toss the pasta, bring the cream, salt, pepper and nutmeg to a simmer, then lower the heat and whisk or swirl in the butter, a chunk at a time. Turn off the heat or remove it from the heat.
Boil and strain your pasta. Toss the pasta in the cream. Sprinkle three quarters of the cheese over the pasta, tossing it to melt and distribute the cheese. Add a little more cream or milk if you've let it get too thick. Serve, sprinkling additional cheese on each.