1 (8 oz.) pkg. size fettuccine
1/2 c. grated Parmesan cheese
2/3 c. sour cream
1/4 lb. butter
1 egg yolk

Cook noodles according to directions on package. While noodles are cooking, beat egg yolk lightly with fork and add to sour cream. Melt butter. Place drained, hot noodles in warm serving bowl or platter. Pour over the noodles, the egg and sour cream mixture, melted butter and about half of the grated cheese. Toss until well blended adding remainder of cheese, a little at a time while tossing. Serve immediately with a green salad and French bread.