from Chez Panisse by Alice Waters
1 head garlic
2 lbs sweet potatoes
2 lbs russet potatoes
salt and pepper
2 cups milk
½-1/2 cup extra virgin olive oil
First roast the garlic. Wrap the head in foil, put in a preheated 400 degree oven and bake for 30-40 minutes or until completely soft. When cool, cut the top free from the head, separate the cloves and set aside. Peel and quarter the sweet potatoes and russet potatoes. Put them in a pot with a steamer insert. Season with a t of salt and steam over medium high heat until cooked, about 20 minutes. Drain, add the roasted cloves of garlic and puree  through a food mill. Return the puree to the pot and reheat over low heat. Scald the milk in a separate saucepan and add from 1-2 cups of the potatoes, depending on how dry they are. Then add the extra virgin olive oil to taste and season with salt and pepper. Serve immediately.