"Combine the garlic and the nuts in a blender or food processor and puree.Add the potatoes, and puree. Pour potato mixture into a bowl and, using a wisk, beat in the lemon juice, a bit at a time. Gradually add the olive oil in a thin stream while continuing to beat so oil combines with potato mixture. When oil has been absorbed, add the egg and beat well. Giovanni de Bourbon- Sicily, French Vogue Note: If you omit the raw egg, you still get a nice sauce."
This came from a lady who uses this sauce for pommes frites she eats in Amsterdam.