Fettuccine noodles
1/2 c. grated Parmesan cheese
1/2 c. sour cream
1/2 lb. sweet butter (I use I Can't Believe It's Not Butter)
1 egg yolk

Cook noodles according to directions. While noodles are cooking, beat egg yolk lightly with a fork and add to sour cream. Melt butter and blend in egg and sour cream mixture. Place drained hot noodles in serving bowl or platter. Pour over the noodles melted butter mixture and about half of the grated cheese. Toss noodles, adding balance of cheese a little at a time while tossing.