Here's another repost. You really need to try this one, it's just heavenly.
Quick Fettuccine Alfredo
1/2 lb. dry fettuccine (although any pasta works in a pinch!)
1 c. heavy cream
1/4 c. butter
1/2 t. salt
3/4 c. Parmesan cheese, freshly grated (not the canned stuff)
pepper to taste
Cook fettuccine in a large saucepan according to package directions. Drain well. In the same saucepan, heat cream, butter, and salt over medium-high heat, bringing to a boil. Remove from heat. Add fettuccine and cheese, tossing to combine well. Continue cooking over low heat, tossing continuously, about 2 minutes or until sauce has thickened. Sprinkle with pepper.