This creamy soup is warm and welcome on a cold winter night.
Preheat oven to 350 degrees Fahrenheit.
Remove loose skin from the garlic head. With a sharp knife, cut off the top one inch from the head of the bulb and discard. Place the garlic in a small oven-proof dish or pan and drizzle with two tablespoons oil. Cover and bake for one hour.
Remove from oven and let cool. Garlic will be soft. Press the softened garlic out of each clove into a small bowl and discard the skins.
In a four-quart saucepot, heat butter until melted. Sauté diced onions over medium-high heat until translucent, about 10 minutes. Add the potatoes, garlic, water, and milk to the pot and heat to boiling. Season with salt and pepper. Lower flame and cook about 20 minutes or until the potatoes are soft.
Using an immersion blender, puree the soup until smooth. Adjust seasonings if necessary. Serve hot with homemade garlic croutons.