(Lee)
2 egg yolks
1 stick salted butter
Lemon juice to taste (1-2 Tbsp.)

In blender, puree eggs and lemon juice.  While the blender is running, slowly drizzle in bubbling butter.  If butter is not hot enough, it will not cook the eggs and the mixture will not thicken.  

NOTE:  This recipe may be doubled, tripled, or even quadrupled.