1 (12 oz.) pkg. ronzoni extra long fettuccine
1/2 c. (1 stick) butter
2/3 c. light cream
1/2 c. grated Parmesan cheese
1 egg yolk, slightly beaten
Or use 2/3 c. sour cream

Cook pasta as directed on package; drain. Meanwhile, melt butter until hot in a medium saucepan. Remove from heat. Gradually stir in light cream, Parmesan cheese, and egg yolk. Pour sauce over hot pasta and toss to coat well. Serve with additional Parmesan cheese, if desired. Makes 6 cups or 6 servings.