Alfredo Sauce - cooking recipe

Ingredients

1/2 c. butter or margarine
2/3 c. light cream or sour cream
1/2 c. grated Parmesan cheese
1 egg yolks, slightly beaten

Preparation

Melt butter until hot in medium saucepan.
Remove from heat. Gradually stir in cream, Parmesan cheese and yolk.
Pour over hot pasta to coat.