Peel and cube Potatoes, then rinse. Put Onions and Potatoes in a pot and cover with water. Bring to a boil and cook untill the Potatoes are quite soft, about 15 minutes. Remove the Potatoes and Oinons to a food processor, and reserve the liquid.
Add crushed Garlic, Olive Oil, Lemon juice, Salt and Pepper to the Onions and Potatoes. Blend untill no longer chunky. Taste and adjust seasoning. Add the reserved boiling water and blend untill creamy. Use more of the boiling water if too dry.
It tastes best if allowed to sit in the refrigerator for an hour or two. Garnish with parsley if you like.
VARIATION: Use roasted garlic instead: Cut the top off one head of garlic and cover in aluminum foil. Place in oven at 400 degrees for about an hour. Continue from step 2.