Alfredo Sauce

3 tablespoons butter
8 fluid ounces heavy whipping cream or half and half
Parsley, pepper & salt to taste
3 tablespoons minced garlic
1/4 cup grated Parmesan cheese
1/4 cup grated Romano cheese
1 egg yolk
2 tablespoons grated Parmesan cheese

Melt butter or margarine with garlic in a saucepan over medium heat until butter is melted & garlic is slightly browned. Add heavy cream, stirring constantly. Stir in salt, pepper, grated Parmesan cheese, and grated Romano cheese. Stir constantly until melted, then mix in egg yolk. Simmer over medium low heat for 3 to 5 minutes. Garnish with additional grated Parmesan cheese, if desired.

Oh yeah & serve warm...duh =)  Enjoy....change anything u wish, that's kind of the way Italian's do things.  Also...if the sauce seems too liquidy, add cornstarch...just a pinch.  
from Pam DeFrancesco