How to cook
Wash and peel the vegetables and cut them into pieces. Place in a thick-bottomed saucepan and pour water to cover them. Boil the vegetables until ready.
Add salt and puree with a hand blender until they become a thick mass, puree. Carefully pour the milk to get the consistency of a soup.
Place back on moderate heat to mix the ingredients. Add the butter cubes.
Serve hot with parmesan croutons.
I buy the croutons ready-made from a specialized bakery store.