Surprisingly enough, there is one correct spelling and it is fettuccine alfredo. Notice that in Italian a doubled consonant sounds long.

The story behind this dubious dish, which is not an Italian recipe, tells about a certain cook in Rome, dude called Alfredo, that invented one of the most boring and bland sauces in the world. The American palate being what it is, gringos just love it.

Since it is not a traditional recipe, there is no canonical way of preparing it. Add spinach. Add tofu. Add grated Bactrian camel thighbone. Do your worse, it is no skin off my nose.

Just one thing more:
> When the noodels are done, strain them and rinse them with hot water so they don't stick together.
This is not necessary, and in fact it may be harmful.