Roasted Potato, Onion, and Garlic Soup
- 2 pounds potatoes, peeled and cut into 1-inch chunks
- 2 yellow onions, peeled and quartered
- 2 tablespoons olive oil
- Salt and freshly-ground black pepper to taste
- 1 head garlic
- 2 1/2 tablespoons unsalted butter
- 2 teaspoons water
- 6 cups vegetable stock 1 1/2 tablespoons unbleached flour
- 1/2 cup milk, half-and-half, or light cream
1. Preheat oven to 400F. Place potatoes and onions in a large bowl, breaking up onions so the layers separate. Drizzle with olive oil, then spread vegetables in a single layer on a large baking sheet or baking pan. Add salt and pepper to taste.
2. Slice off the top third of the head of garlic and place the garlic on a sheet of aluminum foil. Put 1/2 tablespoon butter on cut top of garlic and dribble water on foil, then fold up the sides of the foil to make a packet around the garlic. Place this packet on the baking sheet or in the pan along with the vegetables.
3. Roast everything for 45 minutes, then remove garlic. Continue roasting potatoes and onions another 10 or 15 minutes, until done. Onions will be charred and crisp in places.
4. Put a third of the vegetables in a food processor and add a ladleful of stock. Process until almost smooth, then transfer to a large bowl. Repeat until all the vegetables are professed, squeezing the garlic cloves (they will have softened into a nice paste) into the last batch.
5. Place the remaining stock in a large soup pot and add pureed vegetables. In a small saucepan over moderately low heat, melt the remaining 2 tablespoons of butter and add flour, stirring until the flour turns a light golden color. Stir in the milk or cream and cook, stirring, until thickened. Add a ladle or two full of the soup from the pot to this cream mixture and continue to cook for another minute, stirring to combine.
5. Add the cream mixture to the soup. Heat 10 minutes, stirring, until heated through. Serve hot.