So this isn't really mine but something I learned to make after eating at a restaurant. The original had another hard cheese I can't spell and tasted pretty much like Parmesan, so I just use the easier and cheaper alternative. This is definitely like an Alfredo sauce -heart attack on a plate - but oh, so good. You can not make this with margarine. Only real butter.
Now for those of you who really like curries and food from the Indian cultures, the best way to make this is to take an entire pound of butter, heat on low heat and make a batch of ghee or clarified butter in the process. You want about a 50-50% ratio of milk fat to milk solids, not too chunky but not too oily either. The foam is fine for the dish, but not for the ghee, so make sure you get the milk solids out of the ghee and into the recipe.
Once you have a bunch of the clarified butter pulled off, and your butter is about an even batch, keep cooking it until it starts to turn brown and smells nice and nutty. There is a fine balance to making this, and the trick is not using too high a heat. Also using a non-stick pan helps. Make sure your noodles are cooked (fettuccine and spaghetti both work perfect,) and well drained, put a pile on each of your plates and toss on some Parmesan. I love Parmesan, and when making this I splurge on the shaved stuff or grated, not the cheap powder you get on most pastas. As soon as you have the noodle/Parmesan pile, and your butter is a nice nutty brown not burnt, drizzle the browned butter over the noodles and cheese. It will sizzle slightly, and smell wonderful.
Enjoy with a good green salad and perhaps a chicken breast or some shrimp!