According to my research, the original dish that came to be named Fettucini Alfredo was called fettuccine al burro and consisted of fettucini tossed with butter and cheese and then a second helping of butter. Roman restaurateur Alfredo di Lelio who tripled the butter to great fame – when was more butter ever a bad thing? Today the dish usually involves less butter and some heavy cream – which is a bit healthier and results in sauce with a more appealing feel to the mouth.
Cook fettuccine in a pasta pot of boiling salted water (see my article on reduced water pasta) reserving 1/3 cup cooking water, then drain pasta.
While pasta cooks, bring cream and butter to a simmer in a 12-inch heavy skillet over medium-low heat with salt and pepper. Add fettuccine and 3 tablespoons of reserved water, and cheese to sauce and toss. Add a touch more cooking water if sauce seems too thick to you.
Serve garnished with chopped parsley and additional cheese on the side.
This is a supremely simple dish and every ingredient counts. Use the best fettucini you can find – or make your own (which makes the dish transcendental). Use heavy cream and real butter because anything else will be disappointing – if you want something low-fat, choose another dish. Genuine imported Parmigiano-Reggiano is required – splurge.